Exhibit 99.1

lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll

TRANSOCEAN LTD. REPORTS THIRD QUARTER 2012 RESULTS

·                  Third quarter 2012 revenues were $2.440 billion compared with $2.352 billion in the second quarter 2012;

·                  Operating and maintenance expenses for the third quarter were $1.338 billion, compared with $1.381 billion for the second quarter 2012.  Second quarter operating and maintenance expenses exclude $750 million for estimated loss contingencies associated with the Macondo well incident;

·                  Third quarter 2012 net loss attributable to controlling interest was $381 million, which included $880 million of net unfavorable items primarily associated with the impairment of assets included in discontinued operations.   This compares with the second quarter 2012 net loss attributable to controlling interest of $304 million, which included $621 million of net unfavorable items;

·                  Third quarter Annual Effective Tax Rate(3) from continuing operations was 15.2 percent compared with 28.2 percent in the second quarter 2012;

·                  Third quarter net loss attributable to controlling interest was $1.06 per diluted share.   After adjusting for net unfavorable items, adjusted earnings from continuing operations were $499 million, or $1.37 per diluted share;

·                  Cash flows from operating activities were $786 million in the third quarter, compared with $459 million in the second quarter 2012;

·                  Revenue efficiency(1) from continuing operations was 94.3 percent in the third quarter, compared with 92.1 percent in the second quarter 2012.  Third quarter 2012 Ultra-Deepwater revenue efficiency was 95.8 percent, compared with 92.2 percent in the prior quarter.  Fleet utilization(2) from continuing operations was 77 percent in the third quarter, compared with 72 percent in the second quarter 2012; and

·                  New contracts associated with continuing operations totaling $10.2 billion were secured in the Fleet Status Report periods July 18, 2012 through October 17, 2012.  Backlog from continuing operations was $29.7 billion at October 17th, a net increase of $8.3 billion.

ZUG, SWITZERLAND — Transocean Ltd. (NYSE: RIG) (SIX: RIGN) today reported a net loss attributable to controlling interest of $381 million, or $1.06 per diluted share, for the three months ended

September 30, 2012.  Third quarter 2012 results included net unfavorable items of $880 million, or $2.43 per diluted share.  The results compare with a net loss attributable to controlling interest of $32 million, or $0.10 per diluted share, for the three months ended September 30, 2011.  Third quarter 2011 results included net unfavorable items of $68 million, or $0.21 per diluted share, primarily associated with the company’s acquisition of Aker Drilling.

Net unfavorable items, after tax, impacting the third quarter of 2012 included the following:

·                  $878 million, or $2.43 per diluted share, loss on impairment of assets included in discontinued operations primarily associated with exiting the standard jackup market;

·                  $48 million, or $0.13 per diluted share, net gain on the sale of two floaters, Discoverer 534 and Jim Cunningham;

·                  $30 million, or $0.08 per diluted share, loss from discontinued operations.  This includes $24 million, or $0.06 per diluted share associated with the standard jackups; the remainder is primarily associated with Challenger Minerals (North Sea) Limited; and

·                  $20 million, or $0.05 per diluted share, loss due to discrete taxes and other items.

After adjusting for these net unfavorable items, adjusted earnings from continuing operations were $499 million, or $1.37 per diluted share.  A reconciliation of the non-GAAP adjusted net income and diluted earnings per share is attached.

Operations Quarterly Review

Revenues from continuing operations for the three months ended September 30, 2012 were $2.440 billion, compared with revenues of $2.352 billion during the three months ended June 30, 2012.  Contract drilling revenues increased $136 million mainly due to higher revenue efficiency(1) primarily on Ultra-Deepwater floaters, and lower out of service time.  Revenue efficiency(1) from continuing operations was 94.3 percent for the third quarter, compared with 92.1 percent in the second quarter 2012.  Other revenues decreased $48 million to $130 million for the third quarter 2012, compared with $178 million in the prior quarter, primarily due to decreased levels of low-margin drilling management services activity.

Operating and maintenance expenses from continuing operations decreased $43 million to $1.338 billion for the third quarter of 2012.  This compares with $1.381 billion for the second quarter of 2012, excluding $750 million for estimated loss contingencies associated with the Macondo well incident.  Contract drilling expenses increased by $17 million due to annual pay raises, activity increases, professional fees, and various other items, partly offset by lower costs in the third quarter associated with rigs undergoing surveys, contract preparation or other shipyard projects.  The delayed commencement of shipyard projects favorably impacted contract drilling expenses in the third quarter.  Costs associated with the company’s drilling management services reporting unit decreased $60 million mostly due to reduced activity.

General and administrative expenses were $69 million for the third quarter 2012, compared with $79 million in the previous quarter.  The decrease was primarily due to transaction costs in the second quarter associated with the Quantum exchange of its 50 percent interest in Transocean Pacific Drilling Inc. for Transocean Ltd.’s shares.

Income Taxes

Transocean’s third quarter Effective Tax Rate(4) from continuing operations was 16.5 percent, compared with 5.0 percent in the second quarter 2012.  The increase in the Effective Tax Rate(4) was due to changes in estimates primarily for settlements of prior years’ tax liabilities.  Transocean’s Annual

Effective Tax Rate (3) from continuing operations for the third quarter 2012 was 15.2 percent.  This compares with 28.2 percent for the prior quarter.  The decrease was primarily due to changes in the blend of income that is taxed based on gross revenues versus pre-tax income and rig movements between taxing jurisdictions, among other things.  Third quarter 2012 income tax expense included a favorable adjustment of $31 million, or $0.09 per diluted share, required to reflect a decrease in the Annual Effective Tax Rate(3) to 20.5 percent for the nine months ended September 30, 2012, from 24.6 percent for the first half of 2012.

Other Items

For the third quarter, interest expense, net of amounts capitalized, was $180 million, compared with $183 million in the second quarter 2012.  Capitalized interest for the third quarter 2012 was $12 million, unchanged from the prior quarter.   Interest income increased to $15 million in the third quarter, compared with $13 million in the second quarter 2012.

Cash flows from operating activities were $786 million for the third quarter, compared with $459 million for the second quarter 2012.  Capital expenditures from total operations were $225 million for the third quarter, compared with $236 million in the second quarter of 2012.

Forward-Looking Statements

Statements included in this news release, including those regarding estimates of Transocean’s goodwill or long-lived asset impairments and the estimated loss contingencies associated with the Macondo well incident, are forward-looking statements that involve certain assumptions. These statements are based on currently available competitive, financial, and economic data along with our current operating plans and involve risks and uncertainties including, but not limited to, market conditions, Transocean’s results of operations, the effect and results of litigation, assessments and contingencies, and other factors detailed in “Risk Factors” and elsewhere in Transocean’s filings with the Securities and Exchange Commission. Should one or more of these risks or uncertainties materialize (or the other consequences of such a development worsen), or should underlying assumptions prove incorrect, actual outcomes may vary materially from those forecasted or expected. Transocean disclaims any intention or obligation to update publicly or revise such statements, whether as a result of new information, future events or otherwise.

Conference Call Information

Transocean will conduct a teleconference call at 10:00 a.m. EST, 4:00 p.m. CET, on Monday, November 5, 2012. To participate, dial +1 719-325-4828 and refer to confirmation code 2448847 approximately five to 10 minutes prior to the scheduled start time of the call.

In addition, the conference call will be simultaneously broadcast over the Internet in a listen-only mode and can be accessed by logging onto Transocean’s website at www.deepwater.com and selecting “Investor Relations.” A file containing four charts that may be discussed during the conference call, titled “3Q12 Charts,” has been posted to Transocean’s website and can also be found by selecting “Investor Relations/Quarterly Toolkit.” The conference call may also be accessed via the Internet at www.CompanyBoardroom.com by typing in Transocean’s New York Stock Exchange trading symbol, “RIG.”

A telephonic replay of the conference call should be available after 1:00 p.m. EST, 7:00 p.m. CET, on November 5, 2012, and can be accessed by dialing +1 719-457-0820 or +1 888-203-1112 and referring to the confirmation code 2448847. Also, a replay will be available through the Internet and can

be accessed by visiting either of the above-referenced internet addresses. Both replay options will be available for approximately 30 days.

About Transocean

Transocean is a leading international provider of offshore contract drilling services for oil and gas wells. The company specializes in technically demanding sectors of the global offshore drilling business with a particular focus on deepwater and harsh environment drilling services, and believes that it operates one of the most versatile offshore drilling fleets in the world.

Transocean owns or has partial ownership interests in, and operates a fleet of 115 mobile offshore drilling units consisting of 48 High-Specification Floaters (Ultra-Deepwater, Deepwater and Harsh-Environment drilling rigs), 25 Midwater Floaters, nine High-Specification Jackups, 32 Standard Jackups and one swamp barge. Included in the 115 drilling units, the company has 32 Standard Jackups and one swamp barge classified as discontinued operations. In addition, we have six Ultra-Deepwater Drillships and three High-Specification Jackups under construction.

For more information about Transocean, please visit the website at www.deepwater.com.

Notes

(1) Revenue efficiency is defined as actual revenue divided by the highest amount of total revenue which could have been earned during the relevant period(s). See the accompanying schedule entitled “Revenue Efficiency.”

(2) Utilization is defined as the total actual number of revenue earning days in the period as a percentage of the total number of calendar days in the period for all drilling rigs in the company’s fleet. See the accompanying schedule entitled “Utilization.”

(3) Annual Effective Tax Rate is defined as income tax expense from continuing operations excluding various discrete items (such as changes in estimates and tax on items excluded from income before income tax expense) divided by income from continuing operations before income tax expense excluding gains on sales and similar items pursuant to the accounting standards for income taxes. See the accompanying schedule entitled “Supplemental Effective Tax Rate Analysis.”

(4) Effective Tax Rate is defined as income tax expense from continuing operations divided by income from continuing operations before income taxes. See the accompanying schedule entitled “Supplemental Effective Tax Rate Analysis.”

TRANSOCEAN LTD. AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In millions, except per share data)

(Unaudited)

TRANSOCEAN LTD. AND SUBSIDIARIES

CONDENSED CONSOLIDATED BALANCE SHEETS

(In millions, except share data)

(Unaudited)

TRANSOCEAN LTD. AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(In millions)

(Unaudited)

TRANSOCEAN LTD. AND SUBSIDIARIES

FLEET OPERATING STATISTICS

TRANSOCEAN LTD. AND SUBSIDIARIES

FLEET OPERATING STATISTICS (continued)

TRANSOCEAN LTD. AND SUBSIDIARIES

SUPPLEMENTAL EFFECTIVE TAX RATE ANALYSIS

(In US$ millions, except percentages)