UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (date of earliest event reported): August 22, 2013

NOBLE CORPORATION

(Exact name of Registrant as specified in its charter)

Registrant’s telephone number, including area code: 41 (41) 761-65-55

NOBLE CORPORATION

(Exact name of Registrant as specified in its charter)

Registrant’s telephone number, including area code: (345) 938-0293

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Explanatory Note

This combined filing on Form 8-K is separately filed by Noble Corporation, a Swiss corporation (“Noble-Swiss”), and Noble Corporation, a Cayman Islands company (“Noble-Cayman”). Information in this filing relating to Noble-Cayman is filed by Noble-Swiss and separately by Noble-Cayman on its own behalf. Noble-Cayman makes no representation as to information relating to Noble-Swiss (except as it may relate to Noble-Cayman) or any other affiliate or subsidiary of Noble-Swiss. This report should be read in its entirety as it pertains to each of Noble-Swiss and Noble-Cayman.

Item 1.01 Entry into a Material Definitive Agreement.

On August 22, 2013, Noble-Cayman entered into a $600 million unsecured revolving credit agreement (the “Credit Agreement”), up to $50 million of which is available for swingline loans, with JPMorgan Chase Bank, N.A., as the administrative agent and the swingline lender; the lenders party thereto; Barclays Bank PLC (“Barclays”), Citibank, N.A., Deutsche Bank Securities, Inc. (“DBS”) and Wells Fargo Bank, National Association, as co-syndication agents; BNP Paribas, Credit Agricole Corporate & Investment Bank, Credit Suisse AG, Cayman Islands Branch, Goldman Sachs Bank USA, HSBC Bank USA, N.A., SunTrust Bank and The Bank of Tokyo-Mitsubishi UFJ, Ltd., as co-documentation agents; and J.P. Morgan Securities LLC, Barclays, Citigroup Global Markets, Inc., DBS and Wells Fargo Securities, LLC, as joint lead arrangers and joint lead bookrunners.

Noble-Cayman is the borrower under the Credit Agreement. Additionally, Noble Holding International Limited, a wholly-owned indirect subsidiary of Noble-Cayman (“NHIL”), or such other wholly-owned non-U.S. subsidiary of Noble-Cayman as may be designated by Noble-Cayman and reasonably acceptable to the administrative agent, may be designated as an additional borrower under the Credit Agreement. Upon any such designation, Noble-Cayman will issue a guaranty of the obligations of such additional borrower under the Credit Agreement. NHIL and Noble Drilling Corporation, a wholly-owned indirect subsidiary of Noble-Cayman, are guarantors of the obligations under the Credit Agreement.

Pursuant to the terms of the Credit Agreement, Noble-Cayman may, subject to the satisfaction of certain conditions and successful procurement of additional commitments from new or existing lenders, elect to increase the maximum amount available under the Credit Agreement from $600 million up to an amount not to exceed $800 million. Borrowings under the Credit Agreement may be used for working capital and other general corporate purposes.

The Credit Agreement has an initial term of 364 days and, unless such term is extended, all outstanding borrowings will be due and payable on August 20, 2014. So long as no event of default has occurred and is continuing, Noble-Cayman may request that the term of the Credit Agreement be extended for a 364-day period (and may make successive annual extension requests without limitation). Each such extension is subject to the approval of lenders holding greater than 50% of the commitments then outstanding, and the commitment of any lender that does not consent to an extension of the maturity date will be terminated on the then-effective maturity date.

Revolving borrowings under the Credit Agreement bear interest, at Noble-Cayman’s option, at either (i) the sum of Adjusted LIBOR (as defined in the Credit Agreement), plus a margin ranging between 0.790% to 1.30%, depending on Noble-Cayman’s credit ratings, or (ii) the sum of the Base Rate (as defined in the Credit Agreement), plus a margin ranging between 0% to 0.30%, depending on Noble-Cayman’s credit ratings.

The Credit Agreement contains covenants that Noble-Cayman considers usual and customary for an agreement of this type, including a covenant restricting debt to total tangible capitalization to not greater than 60%. Borrowings under the Credit Agreement are subject to acceleration upon the occurrence of events of default that Noble-Cayman considers usual and customary for an agreement of this type.

The administrative agent and certain of the parties to the Credit Agreement and certain of their respective affiliates have performed in the past, and may perform in the future, banking, investment banking or other advisory services for Noble-Cayman and its affiliates from time to time for which they have received, or will receive, customary fees and expenses.

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The foregoing description is qualified in its entirety by reference to the Credit Agreement and the Guaranty Agreements, copies of which are filed as exhibits to this Current Report on Form 8-K and are incorporated by reference herein. Certain schedules and exhibits to the Credit Agreement have not been filed with such exhibit. Noble-Cayman will furnish supplementally any omitted schedule or exhibit to the U.S. Securities and Exchange Commission upon request.

Statements in this Current Report that are not historical facts, including statements regarding any election by Noble-Cayman to increase the maximum amount available under the credit facility, procurement of commitments from new or existing lenders, future borrowers or guarantors under the credit facility, use of borrowings, the maturity date of the credit facility and interest rates under the credit facility, are forward-looking statements. These forward-looking statements involve certain risks, uncertainties and assumptions, which include but are not limited to actions by current and future lenders, Noble-Cayman’s performance, compliance with covenants, market conditions and other factors detailed in the Company’s most recent Form 10-K, Form 10-Q’s and other filings with the Securities and Exchange Commission. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those indicated.

Item 2.03 Creation of Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information provided in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, each Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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INDEX TO EXHIBITS

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