Exhibit 99.1

TRANSOCEAN LTD. REPORTS SECOND QUARTER 2011 RESULTS

ZUG, SWITZERLAND — Transocean Ltd. (NYSE: RIG) (SIX: RIGN) today reported net income attributable to controlling interest of $155 million, or $0.48 per diluted share, for the three months ended June 30, 2011. The results compare to net income attributable to controlling interest of $715 million, or $2.22 per diluted share, for the three months ended June 30, 2010.

Second quarter 2011 results included the following items, after tax, that resulted in a net unfavorable impact of approximately $36 million, or $0.11 per diluted share:

Second quarter 2011 results also included expenses associated with the Macondo well incident of approximately $26 million, $19 million after tax, or $0.06 per diluted share. These expenses were primarily related to legal costs and professional service fees.

Operations Quarterly Review

Revenues for the three months ended June 30, 2011 were $2.334 billion, compared to revenues of $2.144 billion during the three months ended March 31, 2011. Second quarter contract drilling revenues, which increased to $2.086 billion from $1.95 billion in the first quarter, were positively impacted by improved activity in the Gulf of Mexico, the commencement of operations of the newbuild Ultra-Deepwater Floater Deepwater Champion, the reactivation of previously idled rigs, and higher revenue efficiency for our Ultra-Deepwater and Deepwater Floaters, partially offset by the stacking of additional Deepwater and Midwater Floaters. Overall utilization was flat during the period compared to the first quarter.

Other revenues increased $54 million to $238 million, primarily due to additional drilling management services activity.

The Company reported improved revenue efficiency for our Ultra-Deepwater and Deepwater Floaters compared to the first quarter, as our program to improve efficiency yielded results. Similar to the first quarter, compliance with new well control equipment certification requirements, higher standards for equipment condition and capacity constraints on our vendors continued to adversely impact revenue efficiency and out-of-service time compared to the prior year.

Operating and maintenance expenses totaled $1.492 billion for the second quarter 2011, up from $1.359 billion for the prior quarter. The increase was primarily due to higher maintenance expenses along with increased levels of contract drilling and drilling management services activity.

Net Interest Expense, Capital Expenditures and Cash Flow

Net Interest Expense was $142 million in the period compared to $130 million in the first quarter. The increase is due primarily to interest income associated with a tax refund recognized in the first quarter.

Capital expenditures increased to $293 million for the second quarter compared to $240 million in the first quarter 2011. The higher expenditures were primarily due to our newbuild construction program.

Cash flows from operating activities decreased to $340 million for the second quarter 2011 compared to $390 million for the first quarter 2011. The decrease in cash flows from operations resulted primarily from an increase in working capital.

Effective Tax Rate

Transocean’s second quarter Effective Tax Rate⁽³⁾ was 33.5 percent compared to 33.1 percent in the first quarter. The Company’s Annual Effective Tax Rate⁽⁴⁾ for 2011, which excludes various discrete items, was 22.6 percent in the second quarter compared to 19.3 percent in the first quarter. The increases are primarily due to a shift in activity between tax jurisdictions. Please see the accompanying schedule entitled “Supplemental Effective Tax Rate Analysis.”

Conference Call Information

Transocean will conduct a teleconference call at 10:00 a.m. EDT, 4:00 p.m. CEST, on August 4, 2011. To participate, dial +1 719-457-2698 and refer to confirmation code 4734310 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 to be discussed during the conference call, titled “2Q11 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. EDT, 7:00 p.m. CEST, on August 4, 2011, and can be accessed by dialing +1 719-457-0820 and referring to the confirmation code 4734310. 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 the world’s largest offshore drilling contractor and the leading provider of drilling management services worldwide. With a fleet of 134 mobile offshore drilling units as well as four High-Specification Jackups under construction, Transocean’s fleet is considered one of the most modern and versatile in the world due to its emphasis on technically demanding segments of the offshore drilling business. Transocean owns or operates a contract drilling fleet of 48 High-Specification Floaters (Ultra-Deepwater, Deepwater and Harsh-Environment semisubmersibles and drillships), 25 Midwater Floaters, nine High-Specification Jackups, 51 Standard Jackups and one swamp barge utilized in the support of offshore drilling activities.

(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 our fleet. See the accompanying schedule entitled “Utilization.”

(3) 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.”

(4) 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.”

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

TRANSOCEAN LTD. AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In millions, except per share data)

(Unaudited)

Certain reclassifications have been made to prior period amounts to conform with the current period’s presentation, including reclassifications associated with our discontinued operations. The financial statements contained within this release should be read in conjunction with the consolidated financial statements and notes thereto included in our most recent reports on Form 10-K and Form 10-Q.

TRANSOCEAN LTD. AND SUBSIDIARIES

CONDENSED CONSOLIDATED BALANCE SHEETS

(In millions, except share data)

(Unaudited)

Certain reclassifications have been made to prior period amounts to conform with the current period’s presentation, including reclassifications associated with our discontinued operations. The financial statements contained within this release should be read in conjunction with the consolidated financial statements and notes thereto included in our most recent reports on Form 10-K and Form 10-Q.

TRANSOCEAN LTD. AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(In millions)

(Unaudited)

Certain reclassifications have been made to prior period amounts to conform with the current period’s presentation. The financial statements contained within this release should be read in conjunction with the consolidated financial statements and notes thereto included in our most recent reports on Form 10-K and Form 10-Q.

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 millions, except percentages)