Transocean Ltd.

Three months ended June 30, 2025 compared to the three months ended June 30, 2024

The following is an analysis of our operating results. See “—Performance and Other Key Indicators” for definitions of operating days, average daily revenue, revenue efficiency and rig utilization.

“nm” means not meaningful.

Contract drilling revenues—Contract drilling revenues increased for the three months ended June 30, 2025, compared to the three months ended June 30, 2024, primarily due to the following: (a) approximately $40 million resulting from increased activity for the operations of the newbuild ultra-deepwater floaterDeepwater Aquila, (b) approximately $35 million resulting from higher average daily revenues, (c) approximately $25 million resulting from increased utilization, (d) approximately $20 million resulting from increased reimbursement revenues and (e) approximately $5 million resulting from improved revenue efficiency for the remaining fleet.

Costs and expenses—Operating and maintenance costs and expenses increased for the three months ended June 30, 2025, compared to the three months ended June 30, 2024, primarily due to the following: (a) approximately $40 million resulting from increased activity for the operations of our active fleet, (b) approximately $20 million resulting from increased reimbursable costs, (c) approximately $15 million resulting from the operations of our newbuildDeepwater Aquila and (d) approximately $10 million resulting from the effect of inflation on personnel and other operating costs. These increases were partially offset by the following: (a) approximately $10 million resulting from rigs classified as held for sale and (b) approximately $5 million resulting from costs associated with the early retirement of certain personnel in the three months ended June 30, 2024.

Depreciation and amortization expense decreased for the three months ended June 30, 2025, compared to the three months ended June 30, 2024, primarily due to (a) $19 million resulting from rigs sold or classified as held for sale, partially offset by (b) $11 million resulting from one acquired harsh environment floater, one newbuild ultra-deepwater floater and other equipment placed into service.

General and administrative costs and expenses decreased for the three months ended June 30, 2025, compared to the three months ended June 30, 2024, primarily due to (a) approximately $5 million resulting from decreased legal and professional fees and (b) approximately $4 million resulting from decreased personnel costs, primarily associated with the early retirement of certain personnel in the earlier year.

Impairment or disposal of assets—In the three months ended June 30, 2025, we recognized a loss on impairment of our held-for-sale assets, including the ultra-deepwater floatersDevelopment Driller III,Discoverer Inspiration,Discoverer Luanda and* GSF Development Driller I*, together with related assets. In the three months ended June 30, 2024, we recognized a loss on impairment of our held-for-sale assets, including the ultra-deepwater floaterDeepwater Nautilus and related assets.

In the three months ended June 30, 2025, we recognized an aggregate net gain on disposal of assets unrelated to rig sales.

Other income and expense—Interest expense, net of amounts capitalized, increased in the three months ended June 30, 2025, compared to the three months ended June 30, 2024, primarily due to the following: (a) $40 million increased interest resulting from changes to the fair value of the bifurcated compound exchange feature embedded in the indenture governing the 4.625% senior guaranteed exchangeable bonds due September 2029 (the “4.625% Exchangeable Bonds”), (b) $9 million increased interest resulting from debt issued

• 18 -

in the earlier year and (c) $8 million increased interest resulting from interest costs capitalized for our newbuild construction program completed in the earlier year, partially offset by (d) $14 million decreased interest resulting from debt repaid as scheduled or early retired.

In the three months ended June 30, 2024, we recognized a net gain on retirement of debt as follows: (a) an aggregate net gain of $144 million resulting from retirement of notes validly tendered in the tender offers completed in the period, partially offset by (b) an aggregate net loss of $4 million associated with the redemption and early retirement of $761 million aggregate principal amount of our debt securities.

Other expense, net, increased in the three months ended June 30, 2025, compared to the three months ended June 30, 2024, primarily due to the following: (a) a loss of $24 million associated with the issuance of additional Transocean Ltd. shares to certain holders of 4.00% Exchangeable Bonds in the current-year period pursuant to the Exchange Agreements, (b) a net increased loss of $10 million related to currency exchange rate changes and (c) decreased income of $4 million related to the non-service components of net periodic benefit income.

Income tax expense or benefit—In the three months ended June 30, 2025 and 2024, our effective tax rate was 14.2 percent and 474.5 percent, respectively, based on income or loss before income tax expense or benefit. In the three months ended June 30, 2025 and 2024, the effect of various discrete period tax items was a net tax benefit of $203 million and $7 million, respectively. In the three months ended June 30, 2025, such discrete items included changes to various uncertain tax positions, valuation allowances and rig-basis changes related to impairment. In the three months ended June 30, 2024, such discrete items included changes to deferred taxes due to a loss on the impairment of assets. In the three months ended June 30, 2025 and 2024, our effective tax rate, excluding discrete items, was 70.0 percent and 416.3 percent, respectively, based on income before income tax expense.

Due to our operating activities and organizational structure, our income tax expense or benefit does not change proportionally with our income or loss before income taxes. We may have subsidiaries with tax expense on taxable earnings that exceeds the tax benefits in other jurisdictions, or vice versa, which sometimes results in a negative effective tax rate or unusually large effective tax rates relative to consolidated income or loss before income tax expense or benefit. Our earnings are unevenly distributed across jurisdictions and may experience variability in timing among interim periods throughout the year and such variability may influence the allocation of income tax expense or benefit to the respective interim period. The annual effective tax rate used to allocate income tax expense or benefit to interim periods may also be influenced by the removal of loss jurisdictions from the calculations. Our rig operating structures further complicate our tax calculations, especially in instances where we have more than one operating structure for the taxing jurisdiction and, thus, more than one method of calculating taxes depending on the operating structure utilized by the rig under the contract.

Six months ended June 30, 2025 compared to the six months ended June 30, 2024

The following is an analysis of our operating results. See “—Performance and Other Key Indicators” for definitions of operating days, average daily revenue, revenue efficiency and rig utilization.

“nm” means not meaningful.

Contract drilling revenues—Contract drilling revenues increased for the six months ended June 30, 2025, compared to the six months ended June 30, 2024, primarily due to the following: (a) approximately $85 million resulting from increased utilization, (b) approximately $70 million resulting from increased activity for the operations of the newbuildDeepwater Aquila, (c) approximately

• 19 -

$60 million resulting from higher average daily revenues, (d) approximately $35 million resulting from increased revenue efficiency for the fleet and (e) approximately $25 million resulting from increased reimbursement revenues. These increases were partially offset by approximately $10 million resulting from one less calendar day in the six months ended June 30, 2025.

Costs and expenses—Operating and maintenance costs and expenses increased for the six months ended June 30, 2025, compared to the six months ended June 30, 2024, primarily due to the following: (a) approximately $80 million resulting from increased activity for the operations of our active fleet, (b) approximately $35 million resulting from the operations of our newbuildDeepwater Aquila, (c) a non-cash loss of $34 million in the current period resulting from an unfavorable legal outcome, (d) approximately $25 million resulting from increased reimbursable costs and (e) approximately $20 million resulting from the effect of inflation on personnel and other operating costs. These increases were partially offset by the following: (a) approximately $25 million resulting from rigs classified as held for sale or sold, (b) approximately $10 million resulting from favorable currency exchange rates and (c) approximately $5 million resulting from costs associated with the early retirement of certain personnel in the six months ended June 30, 2024.

Depreciation and amortization expense decreased for the six months ended June 30, 2025, compared to the six months ended June 30, 2024, primarily due to (a) $34 million resulting from rigs sold or classified as held for sale and (b) $5 million resulting from assets that had reached the end of their useful lives or had been retired, partially offset by (c) $23 million resulting from one acquired harsh environment floater, one newbuild ultra-deepwater floater and other equipment placed into service.

General and administrative costs and expenses decreased for the six months ended June 30, 2025, compared to the six months ended June 30, 2024, primarily due to approximately $7 million resulting from decreased personnel costs, primarily associated with the early retirement of certain personnel in the earlier year.

Impairment or disposal of assets—In the six months ended June 30, 2025, we recognized a loss on impairment of our held-for-sale assets, includingDevelopment Driller III,Discoverer Inspiration,Discoverer Luanda and* GSF Development Driller I*,* together with related assets. In the six months ended June 30, 2024, we recognized a loss on impairment of our held-for-sale assets, includingDeepwater Nautilus* and related assets.

In the six months ended June 30, 2025 and 2024, we recognized an aggregate net gain or loss on disposal of assets unrelated to rig sales.

Other income and expense—Interest expense, net of amounts capitalized, increased in the six months ended June 30, 2025, compared to the six months ended June 30, 2024, primarily due to the following: (a) $49 million increased interest resulting from debt issued in the earlier year, (b) $15 million increased interest resulting from interest costs capitalized for our newbuild construction program completed in the earlier year and (c) $14 million increased interest resulting from changes to the fair value of the bifurcated compound exchange feature embedded in the indenture governing the 4.625% Exchangeable Bonds, partially offset by (d) $42 million decreased interest resulting from debt repaid as scheduled or early retired.

In the six months ended June 30, 2024, we recognized a net gain on retirement of debt as follows: (a) an aggregate net gain of $144 million resulting from retirement of notes validly tendered in the tender offers completed in the period, partially offset by (b) an aggregate net loss of $4 million associated with the redemption and early retirement of $761 million aggregate principal amount of our debt securities.

Other expense, net, increased in the six months ended June 30, 2025, compared to the six months ended June 30, 2024, primarily due to the following: (a) a loss of $24 million associated with the issuance of additional Transocean Ltd. shares to certain holders of 4.00% Exchangeable Bonds in the current-year period pursuant to the Exchange Agreements, (b) a net increased loss of $19 million related to currency exchange rate changes and (c) decreased income of $9 million related to the non-service components of net periodic benefit income, partially offset by (d) increased income of $5 million associated with our dual-activity patent.

Income tax expense or benefit—In the six months ended June 30, 2025 and 2024, our effective tax rate was 10.3 percent and 57.8 percent, respectively, based on loss before income tax benefit. In the six months ended June 30, 2025 and 2024, the effect of various discrete period tax items was a net tax benefit of $189 million and $128 million, respectively. In the six months ended June 30, 2025, such discrete items included changes to various uncertain tax positions, valuation allowances and rig-basis changes related to impairment. In the six months ended June 30, 2024, such discrete items included changes to deferred taxes due to rig ownership changes, rig movement and contract expirations across multiple jurisdictions. In the six months ended June 30, 2025 and 2024, our effective tax rate, excluding discrete items, was 268.9 percent and (179.3) percent, respectively, based on income or loss before income tax expense.

Due to our operating activities and organizational structure, our income tax expense or benefit does not change proportionally with our income or loss before income taxes. We may have subsidiaries with tax expense on taxable earnings that exceeds the tax benefits in other jurisdictions, or vice versa, which sometimes results in a negative effective tax rate or unusually large effective tax rates relative to consolidated income or loss before income tax expense or benefit. Our earnings are unevenly distributed across jurisdictions and may experience variability in timing among interim periods throughout the year and such variability may influence the allocation of income tax expense or benefit to the respective interim period. The annual effective tax rate used to allocate income tax expense or benefit to interim periods may also be influenced by the removal of loss jurisdictions from the calculations. Our rig operating structures further complicate our tax calculations, especially in instances where we have more than one operating structure for the taxing jurisdiction and, thus, more than one method of calculating taxes depending on the operating structure utilized by the rig under the contract.

• 20 -