Exhibit 1.1

EXECUTION VERSION

$450,000,000

ATWOOD OCEANICS, INC.

6.50% Senior Notes due 2020

UNDERWRITING AGREEMENT

January 12, 2012

CREDIT SUISSE SECURITIES (USA) LLC

BARCLAYS CAPITAL INC.,

WELLS FARGO SECURITIES, LLC

As Representatives of the Several Underwriters,

c/o Credit Suisse Securities (USA) LLC,

                Eleven Madison Avenue,

                New York, N.Y. 10010-3629

Dear Sirs:

1. Introductory. Atwood Oceanics, Inc., a Texas corporation (“Company”), agrees with the several Underwriters named in Schedule A hereto (“Underwriters”), for whom you are acting as representatives (the “Representatives”), to issue and sell to the several Underwriters $450,000,000 in aggregate principal amount of its 6.50% Senior Notes due 2020 (the “Notes”) under a base indenture, to be dated as of January 18, 2012 (the “Base Indenture”), as supplemented by a supplemental indenture, to be dated as of January 18, 2012 (together with the Base Indenture, the “Indenture”), between the Company and Wells Fargo Bank, National Association, as Trustee.

2. Representations and Warranties of the Company. The Company represents and warrants to, and agrees with, the several Underwriters that:

(a) Filing and Effectiveness of Registration Statement; Certain Defined Terms. The Company has filed with the Commission a registration statement on Form S-3 (No. 333-178937), including a related prospectus or prospectuses, covering the registration of the Notes under the Act, which has become effective. “Registration Statement” at any particular time means such registration statement in the form then filed with the Commission, including any amendment thereto, any document incorporated by reference therein and all 430B Information and all 430C Information with respect to such registration statement, that in any case has not been superseded or modified, and in each case excluding that part of the registration statement constituting the State of Eligibility and Qualification (Form T-1) under the Trust Indenture Act (as defined below) of the Trustee. “Registration Statement” without reference to a time means the Registration Statement as of the Effective Time. For purposes of this definition, 430B Information shall be considered to be included in the Registration Statement as of the time specified in Rule 430B.

For purposes of this Agreement:

“430B Information” means information included in a prospectus then deemed to be a part of the Registration Statement pursuant to Rule 430B(e) or retroactively deemed to be a part of the Registration Statement pursuant to Rule 430B(f).

“430C Information” means information included in a prospectus then deemed to be a part of the Registration Statement pursuant to Rule 430C.

“Act” means the Securities Act of 1933, as amended.

“Applicable Time” means 12:38 pm (Eastern time) on the date of this Agreement.

“Closing Date” has the meaning defined in Section 3 hereof.

“Commission” means the Securities and Exchange Commission.

“Effective Time” of the Registration Statement relating to the Notes means the time of the first contract of sale for the Notes.

“Exchange Act” means the Securities Exchange Act of 1934, as amended.

“Final Prospectus” means the Statutory Prospectus that discloses the public offering price, other 430B Information and other final terms of the Notes and otherwise satisfies Section 10(a) of the Act.

“General Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being so specified in Schedule B to this Agreement.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433, relating to the Notes in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g).

“Limited Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is not a General Use Issuer Free Writing Prospectus.

“Rules and Regulations” means the rules and regulations of the Commission.

“Securities Laws” means, collectively, the Sarbanes-Oxley Act of 2002 (“Sarbanes-Oxley”), the Act, the Exchange Act, the Trust Indenture Act, the Rules and Regulations, the auditing principles, rules, standards and practices applicable to auditors of “issuers” (as defined in Sarbanes-Oxley) promulgated or approved by the Public Company Accounting Oversight Board and, as applicable, the rules of the New York Stock Exchange (“Exchange Rules”).

“Statutory Prospectus” with reference to any particular time means the prospectus relating to the Notes that is included in the Registration Statement immediately prior to that time, including all 430B Information and all 430C Information with respect to the Registration Statement. For purposes of the foregoing definition, 430B Information shall be considered to be included in the Statutory Prospectus only as of the actual time that form of prospectus (including a prospectus supplement) is filed with the Commission pursuant to Rule 424(b) and not retroactively.

“Trust Indenture Act” means the Trust Indenture Act of 1939, as amended.

Unless otherwise specified, a reference to a “rule” is to the indicated rule under the Act.

(b) Compliance with Securities Act Requirements. (i) (A) At the time the Registration Statement initially became effective, (B) at the time of each amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether by post-effective amendment, incorporated report or form of prospectus), (C) at the Effective Time relating to the Notes and (D) on the Closing Date, the Registration Statement conformed and will conform in all material respects to the requirements of the Act, the Trust Indenture Act and the Rules and Regulations and did not and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading and (ii) (A) on its date, (B) at the time of filing the Final Prospectus pursuant to Rule 424(b) and (C) on the Closing Date, the Final Prospectus will conform in all material respects to the requirements of the Act, the Trust Indenture Act and the Rules and Regulations, and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from any such document based upon written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information is that described as such in Section 8(b) hereof.

(c) Automatic Shelf Registration Statement.

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(i) Well-Known Seasoned Issuer Status. (A) At the time of initial filing of the Registration Statement, (B) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether such amendment was by post-effective amendment, incorporated report filed pursuant to Section 13 or 15(d) of the Exchange Act or form of prospectus), and (C) at the time the Company or any person acting on its behalf (within the meaning, for this clause only, of Rule 163(c)) made any offer relating to the Notes in reliance on the exemption of Rule 163, the Company was a “well known seasoned issuer” as defined in Rule 405, including not having been an “ineligible issuer” as defined in Rule 405.

(ii) Effectiveness of Automatic Shelf Registration Statement. The Registration Statement is an “automatic shelf registration statement,” as defined in Rule 405, that initially became effective within three years of the date of this Agreement. If immediately prior to the Renewal Deadline (as hereinafter defined), any of the Notes remain unsold by the Underwriters, the Company will prior to the Renewal Deadline file, if it has not already done so and is eligible to do so, a new automatic shelf registration statement relating to the Notes, in a form reasonably satisfactory to Credit Suisse Securities (USA) LLC (“Credit Suisse”). If the Company is no longer eligible to file an automatic shelf registration statement, the Company will prior to the Renewal Deadline, if it has not already done so, file a new shelf registration statement relating to the Notes, in a form reasonably satisfactory to Credit Suisse, and will use its reasonable best efforts to cause such registration statement to be declared effective within 180 days after the Renewal Deadline. The Company will use its reasonable best efforts to take all other action necessary or appropriate to permit the public offering and sale of the Notes to continue as contemplated in the expired registration statement relating to the Notes. References herein to the Registration Statement shall include such new automatic shelf registration statement or such new shelf registration statement, as the case may be. “Renewal Deadline” means the third anniversary of the initial effective time of the Registration Statement.

(iii) Eligibility to Use Automatic Shelf Registration Form. The Company has not received from the Commission any notice pursuant to Rule 401(g)(2) objecting to use of the automatic shelf registration statement form. If at any time when Notes remain unsold by the Underwriters the Company receives from the Commission a notice pursuant to Rule 401(g)(2) or otherwise ceases to be eligible to use the automatic shelf registration statement form, the Company will (i) promptly notify Credit Suisse, (ii) promptly file a new registration statement or post-effective amendment on the proper form relating to the Notes, in a form reasonably satisfactory to Credit Suisse, (iii) use its reasonable best efforts to cause such registration statement or post-effective amendment to be declared effective as soon as practicable, and (iv) promptly notify Credit Suisse of such effectiveness. The Company will use its reasonable best efforts to take all other action necessary or appropriate to permit the public offering and sale of the Notes to continue as contemplated in the registration statement that was the subject of the Rule 401(g)(2) notice or for which the Company has otherwise become ineligible. References herein to the Registration Statement shall include such new registration statement or post-effective amendment, as the case may be.

(iv) Filing Fees. The Company has paid or shall pay the required Commission filing fees relating to the Notes within the time required by Rule 456(b)(1) without regard to the proviso therein and otherwise in accordance with Rules 456(b) and 457(r).

(d) Ineligible Issuer Status. (i) At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) of the Notes and (ii) at the date of this Agreement, the Company was not and is not an “ineligible issuer,” as defined in Rule 405, including (x) the Company or any other subsidiary in the preceding three years not having been convicted of a felony or misdemeanor or having been made the subject of a judicial or administrative decree or order as described in Rule 405 and (y) the Company in the preceding three years not having been the subject of a bankruptcy petition or insolvency or similar proceeding, not having had a registration statement be the subject of a proceeding under Section 8 of the Act and not being the subject of a proceeding under Section 8A of the Act in connection with the offering of the Notes, all as described in Rule 405.

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(e) General Disclosure Package. As of the Applicable Time, neither (i) the General Use Issuer Free Writing Prospectus(es) issued at or prior to the Applicable Time, the preliminary prospectus, dated January 9, 2012 (the “Preliminary Prospectus”) (which is the most recent Statutory Prospectus distributed to investors generally), and the other information, if any, stated in Schedule B to this Agreement to be included in the General Disclosure Package, all considered together (collectively, the “General Disclosure Package”), nor (ii) any individual Limited Use Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from any Statutory Prospectus or any Issuer Free Writing Prospectus in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(f) Issuer Free Writing Prospectuses. Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Notes or until any earlier date that the Company notified or notifies Credit Suisse as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information then contained in the Registration Statement. If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information then contained in the Registration Statement or as a result of which such Issuer Free Writing Prospectus, if republished immediately following such event or development, would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, (i) the Company has promptly notified or will promptly notify Credit Suisse and (ii) the Company has promptly amended or will promptly amend or supplement such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

(g) Good Standing of the Company. The Company has been duly incorporated and is existing and in good standing under the laws of the State of Texas, with power and authority (corporate and other) to own its properties and conduct its business as described in the General Disclosure Package; and the Company is duly qualified to do business as a foreign corporation and in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to be so qualified would not reasonably be expected, individually or in the aggregate, to have a material adverse effect on the financial condition, results of operations, business or properties of the Company and its subsidiaries taken as a whole (“Material Adverse Effect”).

(h) Subsidiaries. Each subsidiary of the Company has been duly incorporated or organized, as the case may be, and is existing and in good standing under the laws of the jurisdiction of its incorporation or organization, as the case may be, with power and authority (corporate and other) to own its properties and conduct its business as described in the General Disclosure Package; and each subsidiary of the Company is duly qualified to do business as a foreign corporation and in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to be so qualified would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect; all of the issued and outstanding capital stock or other equity interests of each subsidiary of the Company have been duly authorized and validly issued and are fully paid and nonassessable (to the extent that such concepts of “due authorization”, “valid issuance” and being “fully paid and nonassessable” exist in the jurisdiction in which such subsidiary is incorporated or organized, as the case may be ); and the capital stock or other equity interests of each subsidiary owned by the Company, directly or through subsidiaries, is owned free from liens, encumbrances and defects, except as provided pursuant to the Credit Agreement, dated May 6, 2011, among the Company, Atwood Offshore Worldwide Limited, and the various lenders party thereto (as amended, the “Credit Agreement”).

(i) Execution and Delivery of Indenture. The Indenture has been duly authorized by the Company and has been duly qualified under the Trust Indenture Act and the Indenture, when duly executed and delivered in accordance with its terms by each of the parties thereto, will constitute a valid and legally

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binding agreement of the Company, enforceable against the Company in accordance with its terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles.

(j) Notes. The Notes have each been duly authorized by the Company and, when duly executed, authenticated, issued and delivered as provided in the Indenture and paid for as provided herein, such Notes will conform to the information in the General Disclosure Package and to the description of such Notes contained in the Final Prospectus and will constitute valid and legally binding obligations of the Company, enforceable against the Company in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles.

(k) No Finder’s Fee. Except as disclosed in the General Disclosure Package, there are no contracts, agreements or understandings between the Company and any person that would give rise to a valid claim against the Company or any Underwriter for a brokerage commission, finder’s fee or other like payment in connection with this offering.

(l) Registration Rights. Except as disclosed in the General Disclosure Package, there are no contracts or agreements between the Company and any person granting such person the right to require the Company to file a registration statement under the Act with respect to any debt securities of the Company owned or to be owned by such person or to require the Company to include such securities in the securities registered pursuant to a Registration Statement.

(m) Absence of Further Requirements. No consent, approval, authorization, or order of, or filing or registration with, any governmental agency or body or any court is required for the consummation of the transactions contemplated by this Agreement or the Indenture in connection with the offering, issuance and sale of the Notes by the Company, except (i) such as are required under the Securities Laws, (ii) such as have been obtained or made or (iii) such as may be required under state securities laws.

(n) Title to Property. Except as disclosed in the General Disclosure Package, (i) the Company and its subsidiaries have good and marketable title to all real properties and valid title to all other properties and assets owned by them, in each case free from liens, charges, encumbrances and defects that would affect the value thereof or interfere with the use made or to be made thereof by them, except any liens, charges, encumbrances or defects that would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect; (ii) the Company and its subsidiaries hold any leased real or personal property under valid and enforceable leases with no terms or provisions that would interfere with the use made or to be made thereof by them and that, individually or in the aggregate, would reasonably be expected to have a Material Adverse Effect; and (iii) each of the vessels owned by the Company or one of its subsidiaries has been duly registered in the name of the subsidiary of the Company that owns such vessel under the laws and regulations and the flag of the nation of its registration except for any failure to register such vessels that would interfere with the use made or to be made thereof by them and that, individually or in the aggregate, would reasonably be expected to have a Material Adverse Effect.

(o) Absence of Defaults and Conflicts Resulting from Transaction. The execution, delivery and performance of the Indenture and this Agreement, and the issuance and sale of the Notes and compliance with the terms and provisions thereof will not result in a breach or violation of any of the terms and provisions of, or constitute a default or a Debt Repayment Triggering Event (as defined below) under, or result in the imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to (i) the charter or by-laws of the Company or the charter, by-laws or other organizational documents, as the case may be, of any of its subsidiaries, (ii) any statute, rule, regulation or order of any governmental agency or body or any court, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their properties, or (iii) any agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the properties of the Company or any of its subsidiaries is subject; except, in the case of clauses (ii) and (iii) above, for any such conflict, breach, violation, default, lien, charge or encumbrance that would not reasonably be expected, individually or in the aggregate, to have a Material

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Adverse Effect; a “Debt Repayment Triggering Event” means any event or condition that gives, or with the giving of notice or lapse of time would give, the holder of any note, debenture, or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

(p) Absence of Existing Defaults and Conflicts. Neither the Company nor any of its subsidiaries is in violation of its respective charter, by-laws or other organizational documents, as the case may be, or in default (or with the giving of notice or lapse of time would be in default) under any existing obligation, agreement, covenant or condition contained in any indenture, loan agreement, mortgage, lease or other agreement or instrument to which any of them is a party or by which any of them is bound or to which any of the properties of any of them is subject, except such defaults that would not reasonably be expected, individually or in the aggregate, to result in a Material Adverse Effect.

(q) Authorization of Agreement. This Agreement has been duly authorized, executed and delivered by the Company.

(r) Possession of Licenses and Permits. The Company and its subsidiaries possess, and are in compliance with the terms of, all adequate certificates, authorizations, franchises, licenses and permits (“Licenses”) necessary or material to the conduct of the business now conducted or proposed in the General Disclosure Package to be conducted by them and have not received any notice of proceedings relating to the revocation or modification of any Licenses that, if determined adversely to the Company or any of its subsidiaries, would reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(s) Absence of Labor Dispute. No labor dispute with the employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is imminent that would reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(t) Possession of Intellectual Property. The Company and its subsidiaries own, possess or can acquire on reasonable terms, adequate trademarks, trade names and other rights to inventions, know-how, patents, copyrights, confidential information and other intellectual property (collectively, “intellectual property rights”) necessary or material to the conduct of the business now operated by them, or presently employed by them, and have not received any notice of infringement of or conflict with asserted rights of others with respect to any intellectual property rights that, if determined adversely to the Company or any of its subsidiaries, would reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(u) Environmental Laws. Except as disclosed in the General Disclosure Package, (A)(i) neither the Company nor any of its subsidiaries is in violation of, or has any liability under, any federal, state, local or non-U.S. statute, law, rule, regulation, ordinance, code, other requirement or rule of law (including common law), or decision or order of any domestic or foreign governmental agency, governmental body or court, relating to pollution, to the use, handling, transportation, treatment, storage, discharge, disposal or release of Hazardous Substances, to the protection or restoration of the environment or natural resources (including biota), to health and safety including as such relates to exposure to Hazardous Substances, and to natural resource damages (collectively, “Environmental Laws”), (ii) neither the Company nor any of its subsidiaries owns, occupies, operates or uses any real property contaminated with Hazardous Substances, (iii) neither the Company nor any of its subsidiaries is conducting or funding any investigation, remediation, remedial action or monitoring of actual or suspected Hazardous Substances in the environment, (iv) neither the Company nor any of its subsidiaries is liable or allegedly liable for any release or threatened release of Hazardous Substances, including at any off-site treatment, storage or disposal site, (v) neither the Company nor any of its subsidiaries is subject to any claim by any governmental agency or governmental body or person relating to Environmental Laws or Hazardous Substances, and (vi) the Company and its subsidiaries have received and are in compliance with all, and have no liability under any, permits, licenses, authorizations, identification numbers or other approvals required under applicable Environmental Laws to conduct their respective businesses, except in each case covered by clauses (i) – (vi) such as would not reasonably be expected, individually or in the aggregate, to have a Material Adverse

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Effect; (B) to the knowledge of the Company there are no facts or circumstances that would reasonably be expected to result in a violation of, liability under, or claim pursuant to any Environmental Law that would have a Material Adverse Effect; (C) to the knowledge of the Company there are no requirements proposed for adoption or implementation under any Environmental Law that would reasonably be expected to have a Material Adverse Effect; and (D) in the ordinary course of its business, the Company periodically evaluates the effect, including associated costs and liabilities, of Environmental Laws on the business, properties, results of operations and financial condition of it and its subsidiaries, and, on the basis of such evaluation, the Company has reasonably concluded that such Environmental Laws will not, individually or in the aggregate, have a Material Adverse Effect. For purposes of this subsection “Hazardous Substances” means (x) petroleum and petroleum products, by-products or breakdown products, radioactive materials, asbestos-containing materials, polychlorinated biphenyls and mold, and (y) any other chemical, material or substance defined or regulated as toxic or hazardous or as a pollutant, contaminant or waste under Environmental Laws.

(v) Accurate Disclosure. The statements under the headings “Description of Notes” and “Material United States Federal Income Tax Considerations for Non-U.S. Holders” in the General Disclosure Package and the Final Prospectus and under the heading Part I, Item 3 “Legal Proceedings” in the Company’s Annual Report for the year ended September 30, 2011 incorporated by reference in the General Disclosure Package and the Final Prospectus, insofar as such statements summarize legal matters, agreements, documents or proceedings discussed therein, are accurate and fair summaries in all material respects of such legal matters, agreements, documents or proceedings and present the information required to be shown in all material respects.

(w) Absence of Manipulation. The Company has not taken, directly or indirectly, any action that is designed to or that has constituted or that would reasonably be expected to cause or result in the stabilization or manipulation of the price of the Notes.

(x) Statistical and Market-Related Data. Any third-party statistical and market-related data included or incorporated by reference in a Registration Statement, a Statutory Prospectus or the General Disclosure Package are based on or derived from sources that the Company believes to be reliable and accurate.

(y) Internal Controls and Compliance with the Sarbanes-Oxley Act. Except as set forth in the General Disclosure Package, the Company, its subsidiaries and the Company’s Board of Directors (the “Board”) are in compliance in all material respects with Sarbanes-Oxley and all applicable Exchange Rules. The Company maintains a system of internal controls, including, but not limited to, internal controls over accounting matters and financial reporting, an internal audit function and legal and regulatory compliance controls (collectively, “Internal Controls”) that comply with the Securities Laws and are sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with U.S. General Accepted Accounting Principles and to maintain accountability for assets, (iii) access to assets is permitted only in accordance with management’s general or specific authorization and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. The Internal Controls are overseen by the Audit Committee (the “Audit Committee”) of the Board in accordance with Exchange Rules. Since the filing of the Company’s annual report on Form 10-K for the year ended September 30, 2011, the Company has not publicly disclosed or reported to the Audit Committee or the Board, and within the next 90 days the Company does not reasonably expect to publicly disclose or report to the Audit Committee or the Board, a significant deficiency, material weakness, material change in Internal Controls or fraud involving management or other employees who have a significant role in Internal Controls (each, an “Internal Control Event”), any violation of, or failure to comply with, the Securities Laws, or any such matter which, if determined adversely, would reasonably be expected to have a Material Adverse Effect. The Company and its subsidiaries maintain a system of disclosure controls and procedures that complies with the Exchange Act and is sufficient to provide reasonable assurance that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Rules and Regulations, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure.

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(z) Litigation. Except as disclosed in the General Disclosure Package, there are no pending actions, suits or proceedings (including any inquiries or investigations by any court or governmental agency or body, domestic or foreign) against or affecting the Company, any of its subsidiaries or any of their respective properties that, if determined adversely to the Company or any of its subsidiaries, would reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect, or would materially and adversely affect the ability of the Company to perform its obligations under the Indenture or this Agreement, or which are otherwise material in the context of the sale of the Notes; and no such actions, suits or proceedings (including any inquiries or investigations by any court or governmental agency or body, domestic or foreign) are, to the Company’s knowledge, threatened or contemplated.

(aa) Financial Statements. The financial statements, together with the related notes thereto, included in the Registration Statement and the General Disclosure Package present fairly in all material respects the financial position of the Company and its consolidated subsidiaries as of the dates shown and their results of operations and cash flows for the periods shown, and such financial statements have been prepared in conformity with the generally accepted accounting principles in the United States applied on a consistent basis except as otherwise noted therein.

(bb) No Material Adverse Change in Business. Except as disclosed in the General Disclosure Package, since the end of the period covered by the latest audited financial statements included in the General Disclosure Package (i) there has been no change, nor any development or event involving a prospective change, in the financial condition, results of operations, business or properties of the Company and its subsidiaries taken as a whole that is material and adverse, (ii) except as disclosed in or contemplated by the General Disclosure Package, there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock and (iii) except as disclosed in or contemplated by the General Disclosure Package, there has been no material adverse change in the capital stock, short-term indebtedness, long-term indebtedness, net current assets or net assets of the Company and its subsidiaries taken as a whole.

(cc) Investment Company Act. The Company is not and, after giving effect to the offering and sale of the Notes and the application of the proceeds thereof as described in the General Disclosure Package, will not be an “investment company” as defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”).

(dd) Ratings. No “nationally recognized statistical rating organization” as such term is defined under Section 3(a)(62) of the Exchange Act (i) has imposed (or has informed the Company that it is considering imposing) any condition (financial or otherwise) on the Company’s retaining any rating assigned to the Company or any securities of the Company or (ii) has indicated to the Company that it is considering any of the actions described in Section 7(c)(ii) hereof.

(ee) ERISA. (i) There exists no “employee benefit plan” (within the meaning of Section 3(3) of the Employee Retirement Security Act of 1974, as amended (“ERISA”)) that is subject to Title IV of ERISA or Section 412 of the Internal Revenue Code of 1986, as amended (the “Code”), for which the Company or any member of its “Controlled Group” (defined as any organization which is a member of a controlled group of corporations within the meaning of Section 414 of the Code) may have any liability; and (ii) each plan that is intended to be qualified under Section 401(a) of the Code is so qualified and nothing has occurred, whether by action or by failure to act, which would reasonably be expected to cause the loss of such qualification, except where failure to be so qualified would not be reasonably likely to result in a Material Adverse Effect. Neither the Company nor any member of its Controlled Group has any withdrawal or other liability to any “multiemployer plan,” within the meaning of Section 4001(c)(3) of ERISA.

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(ff) No Unlawful Payments. (A) Each of the Company, its subsidiaries and, to the knowledge of the Company, its affiliates and any of their respective officers, directors, supervisors, managers, employees or agents while acting on behalf of the Company, has not violated, the Company’s participation in the offering will not violate, and the Company has instituted and maintains policies and procedures designed to ensure continued compliance with each of the following laws: (i) applicable anti-bribery laws, including but not limited to, any applicable law, rule, or regulation of any locality, including but not limited to any law, rule, or regulation promulgated to implement the OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions, signed December 17, 1997, including the U.S. Foreign Corrupt Practices Act of 1977 or any other law, rule or regulation of similar purpose and scope; (ii) applicable federal, state or foreign anti-money laundering laws or regulations, including, without limitation, Title 18 U.S. Code section 1956 and 1957; or (iii) applicable laws and regulations imposing U.S. economic sanctions measures, including, but not limited to, the International Emergency Economic Powers Act, the Trading with the Enemy Act, the United Nations Participation Act, and the Syria Accountability and Lebanese Sovereignty Act, all as amended, and any Executive Order, directive, or regulation pursuant to the authority of any of the foregoing, including the regulations of the United States Treasury Department set forth under 31 CFR, Subtitle B, Chapter V, as amended, or any orders or licenses issued thereunder, except, in the case of clause (iii), for immaterial violations or noncompliance; and (B) the Company will not use the proceeds of the offering (or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity) for the purpose of financing or facilitating unauthorized activities, or unauthorized dealings with any person, that would result in a violation by the Company of the regulations administered by the Office of Foreign Assets Control of the U.S. Treasury Department.

(gg) Taxes. The Company and its subsidiaries have filed all federal, state, local and non-U.S. tax returns that are required to be filed or have requested extensions thereof (except in any case in which the failure so to file would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect); and, except as set forth in the General Disclosure Package, the Company and its subsidiaries have paid all taxes (including any assessments, fines or penalties) required to be paid by them, except for any such taxes, assessments, fines or penalties currently being contested in good faith or as would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(hh) Insurance. The Company and its subsidiaries are insured by insurers with appropriately rated claims paying abilities against such losses and risks and in such amounts as are prudent and customary for the businesses in which they are engaged; all policies of insurance insuring the Company or any of its subsidiaries or their respective businesses, assets, employees, officers and directors are in full force and effect; the Company and its subsidiaries are in compliance with the terms of such policies and instruments in all material respects; and there are no claims by the Company or any of its subsidiaries under any such policy or instrument as to which any insurance company is denying liability or defending under a reservation of rights clause; neither the Company nor any such subsidiary has been refused any insurance coverage sought or applied for; and neither the Company nor any such subsidiary has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect, except as set forth in or contemplated in the General Disclosure Package.

(ii) Capitalization. The shareholders’ equity and long-term debt of the Company as of September 30, 2011 was as set forth in the General Disclosure Package and Final Prospectus in the column entitled “Actual” under the heading “Capitalization;” and there has not been (1) any subsequent issuance of capital stock of the Company, except as disclosed in the General Disclosure Package or for subsequent issuances, if any, pursuant to any outstanding securities, benefit or compensation plans disclosed in the General Disclosure Package or (2) any subsequent increase, if any, in the outstanding principal amount of long-term indebtedness, except as otherwise disclosed in the General Disclosure Package or under instruments outstanding at September 30, 2011.

(jj) No Restrictions on Subsidiaries. Except as provided in the Credit Agreement, no subsidiary of the Company is currently prohibited, directly or indirectly, under any agreement or other instrument to which it is a party or is subject, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s properties or assets to the Company or any other subsidiary of the Company.

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3. Purchase, Sale and Delivery of Notes. On the basis of the representations, warranties and agreements and subject to the terms and conditions set forth herein, the Company agrees to sell to the several Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price of 98.0% of the principal amount thereof plus accrued interest from January 18, 2012 to the Closing Date, the respective principal amounts of Notes set forth opposite the names of the Underwriters in Schedule A hereto. The yield of the Notes is no lower than the yield recommended by the QIU (as hereinafter defined).

The Company will deliver the Notes to or as instructed by the Representatives for the accounts of the several Underwriters in a form reasonably acceptable to the Representatives against payment of the purchase price by the Underwriters in Federal (same day) funds by wire transfer to an account at a bank acceptable to Credit Suisse drawn to the order of Atwood Oceanics, Inc. at the office of Latham & Watkins LLP, at 9:00 am, New York time, on January 18, 2012, or at such other time not later than seven full business days thereafter as the Representatives and the Company determine, such time being herein referred to as the “Closing Date”. For purposes of Rule 15c6-1 under the Exchange Act, the Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Notes sold pursuant to the offering. The Notes so to be delivered or evidence of their issuance will be made available for checking at the above office of Latham & Watkins LLP at least 24 hours prior to the Closing Date.

4. Offering by Underwriters. It is understood that the several Underwriters propose to offer the Notes for sale to the public as set forth in the General Disclosure Package and the Final Prospectus.

5. Certain Agreements of the Company. The Company agrees with the several Underwriters that:

(a) Filing of Prospectuses. The Company has filed or will file each Statutory Prospectus (including the Final Prospectus) pursuant to and in accordance with Rule 424(b) not later than the second business day following the earlier of the date it is first used or the execution and delivery of this Agreement. The Company has complied and will comply with Rule 433.

(b) Filing of Amendments; Response to Commission Requests. For so long as delivery of a prospectus by an Underwriter or dealer may be (or but for the exception in Rule 172 would be) required under the Act, the Company will promptly advise the Representatives of any proposal to amend or supplement the Registration Statement or any Statutory Prospectus at any time and will offer the Representatives a reasonable opportunity to comment on any such amendment or supplement; and the Company will also advise the Representatives promptly of (i) the filing of any such amendment or supplement, (ii) any request by the Commission or its staff for any amendment to the Registration Statement, for any supplement to any Statutory Prospectus or for any additional information, (iii) the institution by the Commission of any stop order proceedings in respect of the Registration Statement or the threatening of any proceeding for that purpose, and (iv) the receipt by the Company of any notification with respect to the suspension of the qualification of the Notes in any jurisdiction or the institution or threatening of any proceedings for such purpose. The Company will use its reasonable best efforts to prevent the issuance of any such stop order or the suspension of any such qualification and, if issued, to obtain as soon as possible the withdrawal thereof.

(c) Continued Compliance with Securities Laws. If, at any time when a prospectus relating to the Notes is (or but for the exemption in Rule 172 would be) required to be delivered under the Act by any Underwriter or dealer, any event occurs as a result of which the Final Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, or if it is necessary at any time to amend the Registration Statement or supplement the Final Prospectus to comply with the Act, the Company will promptly notify the Representatives of such event and will promptly prepare and file with the Commission and furnish, at its own expense, to the Underwriters and the dealers and any other dealers upon request of the Representatives, an amendment or supplement which will correct such statement or omission or an amendment which will effect such compliance. Neither the Representatives’ consent to, nor the Underwriters’ delivery of, any such amendment or supplement shall constitute a waiver of any of the conditions set forth in Section 7 hereof.

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(d) Rule 158. As soon as practicable, but not later than 16 months, after the date of this Agreement, the Company will make generally available to its securityholders an earnings statement covering a period of at least 12 months beginning after the date of this Agreement and satisfying the provisions of Section 11(a) of the Act and Rule 158.

(e) Furnishing of Prospectuses. The Company will furnish to the Representatives copies of the Registration Statement, including all exhibits, any Statutory Prospectus, the Final Prospectus and all amendments and supplements to such documents, in each case as soon as available and in such quantities as the Representatives reasonably request. The Company will pay the expenses of printing and distributing to the Underwriters all such documents.

(f) Blue Sky Qualifications. The Company will arrange for the qualification of the Notes for sale and the determination of their eligibility for investment under the laws of such jurisdictions as the Representatives designate and will continue such qualifications in effect so long as required for the distribution; provided that in no event shall the Company be obligated to qualify to do business in any jurisdiction where it is not now so qualified or to take any action that would subject it to service of process in suits, other than those arising out of the offering or sale of the Notes, in any jurisdiction where it is not now so subject.

(g) Reporting Requirements. For so long as delivery of a prospectus by an Underwriter or dealer may be (or but for the exception in Rule 172 would be) required under the Act, the Company will furnish to the Representatives and, upon request, to each of the other Underwriters, as soon as practicable after the end of each fiscal year, a copy of its annual report to stockholders for such year; and the Company will furnish to the Representatives (i) as soon as available, a copy of each report and any definitive proxy statement of the Company filed with the Commission under the Exchange Act or mailed to stockholders, and (ii) from time to time, such other information concerning the Company as the Representatives may reasonably request. However, so long as the Company is subject to the reporting requirements of either Section 13 or Section 15(d) of the Exchange Act and is timely filing reports with the Commission on its Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”), it is not required to furnish such reports or statements to the Underwriters.

(h) Payment of Expenses. The Company will pay all expenses incident to the performance of its obligations under this Agreement, including but not limited to(i) any filing fees and other expenses (including reasonable fees and disbursements of counsel to the Underwriters) incurred in connection with qualification of the Notes for sale under the laws of such jurisdictions as the Representatives designate pursuant to Section 5(f) and the preparation and printing of memoranda relating thereto, (ii) any fees charged by investment rating agencies for the rating of the Notes, (iii) costs and expenses related to the review by the Financial Industry Regulatory Authority, Inc. of the Notes (including filing fees), (iv) 50% of the costs and expenses relating to investor presentations or any “road show” in connection with the offering and sale of the Notes including, without limitation, any travel expenses of the Company’s officers and employees and any other expenses of the Company (provided however that the Company shall pay 100% of the costs and expenses of any aircraft chartered in connection with the road show), (v) expenses incurred in distributing preliminary prospectuses and the Final Prospectus (including any amendments and supplements thereto) to the Underwriters and (vi) expenses incurred for preparing, printing and distributing any Issuer Free Writing Prospectuses to investors or prospective investors.

(i) Use of Proceeds. The Company will use the net proceeds received in connection with this offering in the manner described in the “Use of Proceeds” section of the General Disclosure Package and, except as disclosed in the General Disclosure Package, the Company does not intend to use any of the proceeds from the sale of the Notes hereunder to repay any outstanding debt owed to any affiliate of any Underwriter.

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(j) Absence of Manipulation. The Company will not take, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, stabilization or manipulation of the price of the Notes.

(l) Restriction on Sale of Securities. The Company will not offer, sell, contract to sell, pledge or otherwise dispose of, directly or indirectly, or file with the Commission a registration statement under the Act relating to United States dollar-denominated debt securities issued or guaranteed by the Company and having a maturity of more than one year from the date of issue of the Notes, or publicly disclose the intention to make any such offer, sale, pledge, disposition or filing, without the prior written consent of Credit Suisse for a period beginning on the date hereof and ending 90 days after the date hereof.

6. Free Writing Prospectuses. (a) Issuer Free Writing Prospectuses. The Company represents and agrees that, unless it obtains the prior consent of the Representatives, and each Underwriter represents and agrees that, unless it obtains the prior consent of the Company and the Representatives, it has not made and will not make any offer relating to the Notes that would constitute an Issuer Free Writing Prospectus, or that would otherwise constitute a “free writing prospectus,” as defined in Rule 405, required to be filed with the Commission. Any such free writing prospectus consented to by the Company and the Representatives is hereinafter referred to as a “Permitted Free Writing Prospectus.” The Company represents that it has treated and agrees that it will treat each Permitted Free Writing Prospectus as an “issuer free writing prospectus,” as defined in Rule 433, and has complied and will comply with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including timely Commission filing where required, legending and record keeping.

(b) Term Sheets. The Company will prepare a final term sheet relating to the Notes, containing only information that describes the final terms of the Notes and otherwise in a form consented to by the Representatives, and will file such final term sheet within the period required by Rule 433(d)(5)(ii) following the date such final terms have been established for all classes of the offering of the Notes. Any such final term sheet is an Issuer Free Writing Prospectus and a Permitted Free Writing Prospectus for purposes of this Agreement. The Company also consents to the use by any Underwriter of a free writing prospectus that contains only (i)(x) information describing the preliminary terms of the Notes or their offering or (y) information that describes the final terms of the Notes or their offering and that is included in the final term sheet of the Company contemplated in the first sentence of this subsection or (ii) other information that is not “issuer information,” as defined in Rule 433, it being understood that any such free writing prospectus referred to in clause (i) or (ii) above shall not be an Issuer Free Writing Prospectus for purposes of this Agreement.

7. Conditions of the Obligations of the Underwriters. The obligations of the several Underwriters to purchase and pay for the Notes on the Closing Date will be subject to the accuracy of the representations and warranties of the Company herein on the date hereof and as of the Closing Date, to the accuracy of the statements of Company officers made pursuant to the provisions hereof, to the performance by the Company of its obligations hereunder and to the following additional conditions precedent:

(a) Accountants’ Comfort Letter. The Representatives shall have received letters, dated, respectively, the date hereof and the Closing Date, of Pricewaterhouse Coopers LLP confirming that they are a registered public accounting firm and independent public accountants within the meaning of the Securities Laws and substantially in the form of Exhibit A hereto (except that, in the letter dated the Closing Date, the specified date referred to in Exhibit A hereto shall be a date no more than three days prior to the Closing Date).

(b) Filing of Prospectus. The Final Prospectus shall have been filed with the Commission in accordance with the Rules and Regulations and Section 5(a) hereof. No stop order suspending the effectiveness of the Registration Statement or of any part thereof shall have been issued and no proceedings for that purpose shall have been instituted or, to the knowledge of the Company or any Underwriter, shall be contemplated by the Commission.

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(c) No Material Adverse Change. Subsequent to the execution and delivery of this Agreement, there shall not have occurred (i) any change, or any development or event involving a prospective change, in the financial condition, results of operations, business or properties of the Company and its subsidiaries taken as a whole which, in the judgment of the Representatives, is material and adverse and makes it impractical or inadvisable to market the Notes; (ii) any downgrading in the rating of any debt securities of the Company by any “nationally recognized statistical rating organization” (as such term is defined in Section 3(a)(62) of the Exchange Act), or any public announcement that any such organization has under surveillance or review its rating of any debt securities of the Company (other than an announcement with positive implications of a possible upgrading, and no implication of a possible downgrading, of such rating) or any announcement that the Company has been placed on negative outlook; (iii) any change in U.S. or international financial, political or economic conditions or currency exchange rates or exchange controls the effect of which is such as to make it, in the judgment of the Representatives, impractical to market or to enforce contracts for the sale of the Notes, whether in the primary market or in respect of dealings in the secondary market; (iv) any suspension or material limitation of trading in securities generally on the New York Stock Exchange, or any setting of minimum or maximum prices for trading on such exchange; (v) any suspension of trading of any securities of the Company on any exchange or in the over-the-counter market; (vi) any banking moratorium declared by any U.S. federal or New York authorities; (vii) any major disruption of settlements of securities, payment, or clearance services in the United States or (viii) any attack on, outbreak or escalation of hostilities or act of terrorism involving the United States, any declaration of war by Congress or any other national or international calamity or emergency if, in the judgment of the Representatives, the effect of any such attack, outbreak, escalation, act, declaration, calamity or emergency is such as to make it impractical or inadvisable to market the Notes or to enforce contracts for the sale of the Notes.

(d) Opinion of Counsel for the Company. The Representatives shall have received an opinion, dated the Closing Date, from each of (i) Walter A. Baker, Vice President, General Counsel and Corporate Secretary of the Company, substantially in the form attached hereto as Exhibit B and (ii) Baker Botts L.L.P., counsel for the Company, substantially in the form attached hereto as Exhibit C.

(e) Opinion of Counsel for the Underwriters. The Representatives shall have received from Latham & Watkins LLP, counsel for the Underwriters, such opinion or opinions, dated the Closing Date, with respect to such matters as the Representatives may require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(f) Officers’ Certificate. The Representatives shall have received a certificate, dated the Closing Date, of an executive officer of the Company and a principal financial or accounting officer of the Company in which such officers shall state that: the representations and warranties of the Company in this Agreement are true and correct; the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to the Closing Date; no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or, to their knowledge, are threatened by the Commission; and, subsequent to the date of the most recent financial statements in the General Disclosure Package, there has been no material adverse change, nor any development or event involving a prospective material adverse change, in the financial condition, results of operations, business or properties of the Company and its subsidiaries taken as a whole except as set forth in the General Disclosure Package or as described in such certificate.

The Company will furnish the Representatives with such conformed copies of such opinions, certificates, letters and documents as the Representatives reasonably request. Credit Suisse may in its sole discretion waive on behalf of the Underwriters compliance with any conditions to the obligations of the Underwriters hereunder.

8. Indemnification and Contribution. (a) Indemnification of Underwriters. The Company will indemnify and hold harmless each Underwriter, its partners, members, directors, officers, employees, agents, affiliates and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each, an “Indemnified Party”), against any and all losses, claims, damages or liabilities, joint or several, to which such Indemnified Party may become subject, under the Act, the Exchange Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained in any part of the Registration Statement at any time, or the omission or the alleged omission of a

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material fact required to be stated therein or necessary to make the statements therein not misleading or (ii) any untrue statement or alleged untrue statement of any material fact contained in any part of any Statutory Prospectus, the Final Prospectus or any Issuer Free Writing Prospectus or the omission or the alleged omission of a material fact necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, and will reimburse each Indemnified Party for any legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending against any loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to any of the above as such expenses are incurred; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement in or omission or alleged omission from any of such documents in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in subsection (b) below.

(b) Indemnification of Company. Each Underwriter will severally and not jointly indemnify and hold harmless the Company, each of its directors and each of its officers who signs a Registration Statement and each person, if any, who controls the Company within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each, an “Underwriter Indemnified Party”), against any losses, claims, damages or liabilities to which such Underwriter Indemnified Party may become subject, under the Act, the Exchange Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of any material fact contained in any part of the Registration Statement at any time or the omission or the alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading or (ii) any untrue statement or alleged untrue statement of any material fact contained in any part of any Statutory Prospectus, the Final Prospectus or any Issuer Free Writing Prospectus or the omission or the alleged omission of a material fact necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives specifically for use therein, and will reimburse any legal or other expenses reasonably incurred by such Underwriter Indemnified Party in connection with investigating or defending against any such loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Underwriter Indemnified Party is a party thereto), whether threatened or commenced, based upon any such untrue statement or omission, or any such alleged untrue statement or omission as such expenses are incurred, it being understood and agreed that the only such information furnished by any Underwriter consists of the following information in the Final Prospectus furnished on behalf of each Underwriter (i) the names of the underwriters, (ii) the table under the first paragraph under the caption “Underwriting”, (iii) the concession and reallowance figures appearing in the third paragraph under the caption “Underwriting”; (iv) the fourth paragraph under the caption “Underwriting”; and (v) the paragraphs under the caption “Underwriting—Stabilization and Market Making.”

(c) Actions against Parties; Notification. Promptly after receipt by an indemnified party under this Section or Section 9 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under subsection (a) or (b) above or Section 9, notify the indemnifying party of the commencement thereof; but the failure to notify the indemnifying party shall not relieve it from any liability that it may have under subsection (a) or (b) above or Section 9 except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided further that the failure to notify the indemnifying party shall not relieve it from any liability that it may have to an indemnified party otherwise than under subsection (a) or (b) above or Section 9. In case any such action is brought against any indemnified party and it notifies the indemnifying party of the commencement thereof, the indemnifying party will be entitled to participate therein and, to the extent that it may wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party will not be liable to such indemnified party under this Section or Section 9, as the case may be, for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense

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thereof other than reasonable costs of investigation. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened action in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party unless such settlement (i) includes an unconditional release of such indemnified party from all liability on any claims that are the subject matter of such action and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act by or on behalf of an indemnified party.

(d) Contribution. If the indemnification provided for in this Section is unavailable or insufficient to hold harmless an indemnified party under subsection (a) or (b) above, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of the losses, claims, damages or liabilities referred to in subsection (a) or (b) above (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Notes or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The amount paid by an indemnified party as a result of the losses, claims, damages or liabilities referred to in the first sentence of this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any action or claim which is the subject of this subsection (d). Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Notes underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this subsection (d) to contribute are several in proportion to their respective underwriting obligations and not joint. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 8(d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to in this Section 8(d).

(e) The obligations of the Company under this Section and Section 9 shall be in addition to any liability which the Company may otherwise have and shall extend, upon the same terms and conditions, to each person, if any, who controls any Underwriter or the QIU within the meaning of the Act; and the obligations of the Underwriters under this Section shall be in addition to any liability which the respective Underwriters may otherwise have and shall extend, upon the same terms and conditions, to each director of the Company, to each officer of the Company who has signed a Registration Statement and to each person, if any, who controls the Company within the meaning of the Act.

9. Qualified Independent Underwriter. The Company hereby confirms that at its request Credit Suisse has without compensation acted as “qualified independent underwriter” (in such capacity, the “QIU”) within the meaning of Rule 5121 of the Conduct Rules of the Financial Industry Regulatory Authority, Inc. in connection with the offering of the Notes. The Company will indemnify and hold harmless the QIU against any losses, claims, damages or liabilities, joint or several, to which the QIU may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon the QIU’s acting (or alleged failing to act) as such “qualified independent underwriter” and will reimburse the QIU for any legal or other expenses reasonably incurred by the QIU in connection with investigating or defending any such loss, claim, damage, liability or action as such expenses are incurred; provided, however, that the Company shall not be liable in any such case to the extent that any such loss, claim, damage, liability or expense results from the gross negligence or willful misconduct of the QIU.

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10. Default of Underwriters. If any Underwriter or Underwriters default in their obligations to purchase Notes hereunder on the Closing Date and the aggregate principal amount of Notes that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total principal amount of Notes that the Underwriters are obligated to purchase on the Closing Date, Credit Suisse may make arrangements satisfactory to the Company for the purchase of such Notes by other persons, including any of the Underwriters, but if no such arrangements are made by the Closing Date, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Notes that such defaulting Underwriters agreed but failed to purchase on the Closing Date. If any Underwriter or Underwriters so default and the aggregate principal amount of Notes with respect to which such default or defaults occur exceeds 10% of the total principal amount of Notes that the Underwriters are obligated to purchase on the Closing Date and arrangements satisfactory to Credit Suisse and the Company for the purchase of such Notes by other persons are not made within 36 hours after such default, this Agreement will terminate without liability on the part of any non-defaulting Underwriter or the Company, except as provided in Section 11. As used in this Agreement, the term “Underwriter” includes any person substituted for an Underwriter under this Section. Nothing herein will relieve a defaulting Underwriter from liability for its default.

11. Survival of Certain Representations and Obligations. The respective indemnities, agreements, representations, warranties and other statements of the Company or its officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation, or statement as to the results thereof, made by or on behalf of any Underwriter, the Company or any of their respective representatives, officers or directors or any controlling person, and will survive delivery of and payment for the Notes. If the purchase of the Notes by the Underwriters is not consummated for any reason other than because of the termination of this Agreement pursuant to Section 10 hereof or the occurrence of any event specified in clause (iii), (iv), (vi), (vii) or (viii) of Section 7(c) hereof, the Company will reimburse the Underwriters for all out-of-pocket expenses (including fees and disbursements of counsel) reasonably incurred by them in connection with the offering of the Notes, and the respective obligations of the Company and the Underwriters pursuant to Section 8 hereof shall remain in effect. In addition, if any Notes have been purchased hereunder, the representations and warranties in Section 2 and all obligations under Section 5 shall also remain in effect.

12. Notices. All communications hereunder will be in writing and, if sent to the Underwriters or the QIU, will be mailed, delivered or telegraphed and confirmed to the Representatives, c/o Credit Suisse Securities (USA) LLC, Eleven Madison Avenue, New York, N.Y. 10010-3629, Attention: LCD-IBD, or, if sent to the Company, will be mailed, delivered or telegraphed and confirmed to it at Atwood Oceanics, Inc., 15835 Park Ten Place Drive, Houston, Texas 77218, Attention: General Counsel, provided, however, that any notice to an Underwriter pursuant to Section 8 will be mailed, delivered or telegraphed and confirmed to such Underwriter.

13. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and controlling persons referred to in Section 8, and no other person will have any right or obligation hereunder.

14. Representation of Underwriters. The Representatives will act for the several Underwriters in connection with this financing, and any action under this Agreement taken by the Representatives jointly or by Credit Suisse will be binding upon all the Underwriters.

15. Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same Agreement.

16. Absence of Fiduciary Relationship. The Company acknowledges and agrees that:

(a) No Other Relationship. The Representatives have been retained solely to act as underwriters in connection with the sale of Notes and that no fiduciary, advisory or agency relationship between the Company and the Representatives has been created in respect of any of the transactions contemplated by this Agreement or the Final Prospectus, irrespective of whether the Representatives have advised or are advising the Company on other matters;

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(b) Arms’ Length Negotiations. The price of the Notes set forth in this Agreement was established by the Company following discussions and arms-length negotiations with the Representatives and the Company is capable of evaluating and understanding and understands and accepts the terms, risks and conditions of the transactions contemplated by this Agreement;

(c) Absence of Obligation to Disclose. The Company has been advised that the Representatives and their affiliates are engaged in a broad range of transactions which may involve interests that differ from those of the Company and that the Representatives have no obligation to disclose such interests and transactions to the Company by virtue of any fiduciary, advisory or agency relationship;

(d) Waiver. The Company waives, to the fullest extent permitted by law, any claims it may have against the Representatives for breach of fiduciary duty or alleged breach of fiduciary duty arising out of the transactions contemplated by this Agreement and agrees that the Representatives shall have no liability (whether direct or indirect) to the Company in respect of such a fiduciary duty claim or to any person asserting a fiduciary duty claim on behalf of or in right of the Company, including stockholders, employees or creditors of the Company; and

(e) Research Analyst Independence. The Company acknowledges that the Underwriters’ research analysts and research departments are required to be independent from their respective investment banking divisions and are subject to certain regulations and internal policies, and that such Underwriters’ research analysts may hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering that differ from the views of their respective investment banking divisions. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the Underwriters with respect to any conflict of interest that may arise from the fact that the views expressed by their independent research analysts and research departments may be different from or inconsistent with the views or advice communicated to the Company by such Underwriters’ investment banking divisions. The Company acknowledges that each of the Underwriters is a full service securities firm and as such from time to time, subject to applicable securities laws, may effect transactions for its own account or the account of its customers and hold long or short positions in debt or equity securities of the Company that may be the subject of the transactions contemplated by this Agreement.

17. Applicable Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York.

The Company hereby submits to the non-exclusive jurisdiction of the Federal and state courts in the Borough of Manhattan in The City of New York in any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. The Company irrevocably and unconditionally waives any objection to the laying of venue of any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby in Federal and state courts in the Borough of Manhattan in The City of New York and irrevocably and unconditionally waives and agrees not to plead or claim in any such court that any such suit or proceeding in any such court has been brought in an inconvenient forum.

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If the foregoing is in accordance with the Representatives’ understanding of our agreement, kindly sign and return to the Company one of the counterparts hereof, whereupon it will become a binding agreement between the Company and the several Underwriters in accordance with its terms.

Very truly yours,

Signature Page to Underwriting Agreement

The foregoing Underwriting Agreement is hereby confirmed and accepted as of the date first above written.

Acting on behalf of themselves and as the Representatives of the several Underwriters

Signature Page to Underwriting Agreement

SCHEDULE A

SCHEDULE B

“General Use Issuer Free Writing Prospectus” includes each of the following documents:

1. Final term sheet, dated January 12, 2012, a copy of which is attached hereto.

The following information is also included in the General Disclosure Package:

None.