Exhibit 99.1

TRANSOCEAN LTD. REPORTS FOURTH QUARTER

AND FULL YEAR 2011 RESULTS

·                  Revenues improved eight percent in the fourth quarter to $2.422 billion compared to $2.242 billion in the third quarter 2011,

·                  Fourth quarter 2011 net loss attributable to controlling interest was $6.119 billion, which included $ 6.176 billion of certain net unfavorable items including an estimated goodwill impairment of $5.2 billion and an estimated loss contingency of $1.0 billion associated with the Macondo Well incident, compared to a net loss attributable to controlling interest of $71 million in the third quarter 2011, which included $81 million of certain net unfavorable items,

·                  Revenue efficiency(1) was 91.9 percent in the fourth quarter, up from 89.5 percent in the third quarter 2011,

·                  Fleet utilization(2) was 61 percent in the fourth quarter, up from 58 percent in the third quarter 2011,

·                  Excluding $1.0 billion for estimated loss contingencies associated with the Macondo Well incident, fourth quarter 2011 operating and maintenance expenses were $1.565 billion, up from $1.540 billion in the third quarter 2011,

·                  Cash flows from operating activities were $563 million in the fourth quarter, up from $492 million in the third quarter 2011,

·                  The Annual Effective Tax Rate(3) for 2011 increased to 41.3 percent from 34.1 percent in the third quarter 2011, and

·                  New contracts totaling $1.4 billion were secured in the Fleet Status Report period October 17, 2011 through February 14, 2012.

ZUG, SWITZERLAND — Transocean Ltd. (NYSE: RIG) (SIX: RIGN) today reported a net loss attributable to controlling interest of $6.119 billion, or $18.62 per diluted share, for the three months ended December 31, 2011. The results compare to a net loss attributable to controlling interest of $799 million, or $2.51 per diluted share, for the three months ended December 31, 2010.

Fourth quarter 2011 results included the following items, after tax, which resulted in a net adverse impact of $ 6.176 billion, or $18.80 per diluted share:

·                  An estimated, non-cash charge of $5.2 billion, or $15.83 per diluted share, resulting from a goodwill impairment associated with the contract drilling services reporting unit. The impairment was primarily due to a decline in the market valuation of the contract drilling services business,

·                  $1.0 billion, or $3.04 per diluted share, for estimated loss contingencies associated with the Macondo Well incident that the company believes is probable and for which a reasonable estimate can be made at this time.  This estimate will be adjusted to reflect new information and future developments as they become known,

·                  $30 million, or $0.09 per diluted share, of charges associated with the company’s acquisition of Aker Drilling,

·                  $26 million, or $0.08 per diluted share,  of income from discontinued operations, primarily related to the gain on the sale of Challenger Minerals (North Sea) Limited,

·                  $18 million, or $0.05 per diluted share,  of favorable discrete tax items, and

·                  $11 million, or $0.03 per diluted share, from the gain on the sale of the GSF Adriatic XI.

Fourth quarter 2011 also included pre-tax expenses associated with the Macondo well incident of approximately $11 million, or $0.01 per diluted share. These expenses were primarily related to legal costs and other professional fees that are not expected to be recoverable from insurance.

Transocean’s fourth quarter Effective Tax Rate(4) was (2.2) percent compared to 212.8 percent in the third quarter 2011.  The decrease in the Effective Tax Rate was due primarily to the impact of the estimated $5.2 billion goodwill impairment and the estimated loss contingency of $1.0 billion associated with the Macondo Well incident.  The 2011 Annual Effective Tax Rate(3) of 41.3 percent excludes $18 million of various discrete items which reduced income tax expense in the fourth quarter. The increase to 41.3 percent in the fourth quarter from 34.1 percent in the third quarter 2011 was primarily due to lower full year profitability than expected.  Fourth quarter 2011 income tax expense included an adjustment of $46 million, or $0.14 per diluted share, required to reflect an increase in the Annual Effective Tax Rate(3) from 34.1 percent for the first nine months of 2011.

The relationship between our provision for income taxes and pre-tax income can vary materially from period to period.  However, significant decreases in profitability generally result in higher effective tax rates and, conversely, significant increases in profitability generally result in lower effective tax rates.  A more detailed explanation of the factors impacting our effective tax rate can be found in our 2011 Annual Report on form 10-K but include, among others, changes in the blend of income that is taxed based on gross revenues versus pre-tax income, rig movements between taxing jurisdictions, and our rig operating structures.

Please see the accompanying schedule entitled “Supplemental Effective Tax Rate Analysis.”

Revenues for the three months ended December 31, 2011 were $2.422 billion, an eight percent improvement compared to revenues of $2.242 billion during the three months ended September 30, 2011.   The $180 million increase in revenues was primarily due to the two Harsh Environment semi-submersible rigs added through the acquisition of Aker Drilling and higher utilization, primarily on Deepwater Floaters, several of which were in the shipyard during the third quarter 2011.   Fourth quarter revenue efficiency also improved to 91.9 percent, up from 89.5 percent in the third quarter 2011.

Operating and maintenance expenses totaled $2.565 billion for the fourth quarter 2011, up from $1.540 billion for the prior quarter.  The increase of $1.025 billion was due primarily to $1.0 billion of estimated loss contingencies associated with the Macondo Well incident.  Additionally, approximately $25 million in costs was related to the addition of the two Aker semi-submersible rigs and unplanned charges associated with the contract termination of the Deepwater Expedition.  These costs were partially offset primarily by lower operating and maintenance expenses associated with rigs undergoing shipyard, maintenance, repair and equipment certification projects during the period, and other favorable items.

General and administrative expenses were $88 million for the fourth quarter 2011 compared to $67 million in the previous quarter.  The $21 million increase was primarily due to Aker acquisition costs.

For the fourth quarter, Interest expense, net of amounts capitalized, was $178 million, compared to $151 million in the third quarter 2011, reflecting the acquisition of Aker Drilling and the issuance of the $2.5 billion new senior notes during the period.  Capitalized interest for the fourth quarter 2011 was $10 million compared to $5 million in the prior quarter.   Interest income increased to $17 million in the fourth quarter 2011, compared to $7 million in the third quarter, primarily associated with cash investments restricted for payment of certain debt instruments assumed in the Aker acquisition.

Cash flows from operating activities increased $71 million to $563 million for the fourth quarter 2011 compared to $492 million for the third quarter 2011 due to improved operating results.

Full Year 2011

For the year ended December 31, 2011, net loss attributable to controlling interest totaled $5.725 billion, or $17.79 per diluted share, resulting primarily from the estimated goodwill impairment of $5.2 billion, or $16.15 per diluted share, associated with the contract drilling services reporting unit and the estimated loss contingencies of $1.0 billion, or $3.11 per diluted share, associated with the Macondo Well incident.  Additionally, approximately $71 million, or $0.13 per diluted share, of expense was incurred primarily related to legal costs and other professional fees that are not expected to be recoverable from insurance.  Partially offsetting these charges were net favorable items for the full year totaling $46 million, or $0.15 per diluted share, and included the following:

·                  $197 million, or $0.62 per diluted share, from the gain on the sale of discontinued operations of the Trident 20 and Challenger Minerals (North Sea) Limited,

·                  $113 million, or $0.36 per diluted share, of charges associated with the acquisition of Aker Drilling, including $78 million resulting from a forward foreign exchange contract executed to address potential exchange rate variability, $22 million for acquisition costs, and $13 million related to losses on a marketable security,

·                  $42 million or $0.12 per diluted share, of charges primarily related to discrete tax and other items,

·                  $33 million, or $0.10 per diluted share, from the gain on the sale of the Transocean Mercury and the GSF Adriatic XI, and including the sale of the equity interest in Overseas Drilling Limited, which owns the research vessel Joides Resolution, and

·                  $29 million or $0.09 per diluted share, loss on impairment primarily relating to the sale of the George H. Galloway, GSF Labrador, GSF Britannia, and the Searex IV.

Interest expense, net of amounts capitalized, was $621 million, compared to $567 million for the full year 2010.  Capitalized interest for the full year 2011 was $39 million compared to $89 million in 2010.   Interest income was $44 million for the full year 2011 compared to $23 million in 2010.

For the full year 2011, cash flow from operating activities totaled $1.785 billion compared to $3.946 billion for 2010 with the decrease primarily due to lower operating results.

For the year ended December 31, 2010, net income attributable to controlling interest totaled $961 million, or $2.99 per diluted share. Net income for the year ended December 31, 2010, included after-tax net charges of $819 million, or $2.54 per diluted share, resulting primarily from the $1 billion impairment of the Standard Jackups. After-tax net charges for the full year 2010 also included amounts associated with litigation matters, discontinued operations, an impairment of oil and gas properties, a loss on the sale of two rigs and losses on the early retirement of debt, and other matters totaling $76 million, partially offset by a $267 million after-tax gain resulting from insurance recoveries associated with the loss of the Deepwater Horizon.

Full year 2010 results also included expenses associated with the Macondo well incident of $137 million, or $116 million after tax, or $0.36 per diluted share. These expenses included legal costs, internal investigation costs, professional fees that are not expected to be recovered by insurance, and increased insurance premiums.

Full Year 2012 Guidance Summary

The following table is a summary of the company’s full year 2012 guidance for key income statement and balance sheet items.  This information is based on current expectations and certain management assumptions, and is subject to change.

*  Other Revenues includes Drilling Management Services, recharge revenues, and other miscellaneous revenues

** Net Interest Expense is net of capitalized interest of approximately $40 million and Interest Income of approximately $50 million

Forward-Looking Statements

Statements included in this news release regarding Transocean’s full year 2012 guidance, the estimate of Transocean’s goodwill impairment for the fiscal year ended December 31, 2011, 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 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. ET, 4:00 p.m. CET, on February 27, 2012. To participate, dial +1 719-325-4781 and refer to confirmation code 6384703 approximately 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 three charts that may be discussed during the conference call, titled “4Q11 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. ET, 7:00 p.m. CET, on February 27, 2012, and can be accessed by dialing +1 719-457-0820 or +1 888-203-1112 and referring to the confirmation code 6384703. 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.  Transocean owns or has partial ownership interests in and operates a fleet of 132 mobile offshore drilling units consisting of 50 High-Specification Floaters (Ultra-Deepwater, Deepwater and Harsh-Environment semisubmersibles and drillships), 25 Midwater Floaters, nine High-Specification Jackups, 47 Standard Jackups and one swamp barge.  In addition, we have two Ultra-Deepwater Drillships and four High-Specification Jackups under construction.  Transocean specializes in technically demanding sectors of the global offshore drilling business with a particular focus on deepwater and harsh environment drilling services.  We believe we operate one of the most versatile offshore drilling fleets in the world.

(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.”

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

TRANSOCEAN LTD. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF OPERATIONS

(In millions, except per share data)

(Unaudited)

TRANSOCEAN LTD. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(In millions, except share data)

(Unaudited)

TRANSOCEAN LTD. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In millions)

(Unaudited)

TRANSOCEAN LTD. AND SUBSIDIARIES

FLEET OPERATING STATISTICS

(1)          Average daily revenue is defined as contract drilling revenue earned per revenue earning day in the period.  A revenue earning day is defined as a day for which a rig earns dayrate after commencement of operations.

TRANSOCEAN LTD. AND SUBSIDIARIES

FLEET OPERATING STATISTICS (continued)

(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 our fleet.

(3)          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).

TRANSOCEAN LTD. AND SUBSIDIARIES

SUPPLEMENTAL EFFECTIVE TAX RATE ANALYSIS

(In US$ millions, except percentages)