Company: RIG
Filing Date: 2025-09-24
Form Type: 424B5
Source: 0001451505-25-000097
Chunk: 102

Company: Transocean Ltd.
Filing Date: 2025-09-24
Form: 424B5
Chunk 102
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### VALIDITY OF THE SECURITIES
The validity of the securities offered hereby will be passed upon by Carey Olsen, Grand Cayman, Cayman Islands, as to matters of Cayman Islands law, by Baker Botts L.L.P., Houston, Texas, as to certain matters relating to U.S. law and by Homburger AG, Zurich, Switzerland as to matters of Swiss law. Any underwriters will be advised about matters relating to any offering by their own legal counsel.

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### EXPERTS
The consolidated financial statements of Transocean Ltd. and subsidiaries appearing in Transocean Ltd.’s Annual Report (Form 10-K) for the year ended December 31, 2023 (including the schedule appearing therein), and the effectiveness of Transocean Ltd. and subsidiaries’ internal control over financial reporting as of December 31, 2023, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

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#### Transocean Ltd.

#### 100,000,000 Shares
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#### Preliminary Prospectus Supplement
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#### Citigroup

#### Morgan Stanley

#### , 2025