Company: RIG
Filing Date: 2025-09-24
Form Type: 424B5
Source: 0001451505-25-000097
Chunk: 57

Company: Transocean Ltd.
Filing Date: 2025-09-24
Form: 424B5
Chunk 57
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<div align='center'>S-35</div>

INCORPORATION BY REFERENCE The SEC allows us to “incorporate by reference” the information we have filed with it, which means that we can disclose important information to you by referring you to those documents filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus supplement, and subsequent information that we file with the SEC will automatically update and supersede that information. We have incorporated by reference the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (other than information “furnished” and not “filed” with the SEC, unless we specifically provide that such “furnished” information is to be incorporated by reference) until the completion or termination of this offering. The documents we incorporate by reference are:

Any statement contained in a document incorporated or deemed to be incorporated by reference into this prospectus supplement will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement or any other subsequently filed document that is deemed to be incorporated by reference into this prospectus supplement modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. A copy of these filings will be provided upon oral or written request, other than an exhibit to these filings unless we have specifically incorporated that exhibit by reference into the filing, at no cost. You may request such copies by writing or calling: Transocean Ltd. c/o Transocean Offshore Deepwater Drilling Inc. 1414 Enclave Parkway Houston, Texas 77077 Attn: Investor Relations +1 (713) 232-7500

S-36

PROSPECTUS

<div align='center'>Transocean Ltd.

SharesWarrantsPurchase ContractsRightsUnitsGuarantees

Transocean Inc.

Debt SecuritiesWarrantsPurchase ContractsRightsUnits</div>

Transocean Ltd. or Transocean Inc. will provide the specific terms of the securities in supplements to this prospectus. The securities may be offered separately or together in any combination or as separate series. You should read this prospectus and any supplement carefully before you invest.

Transocean Ltd.’s shares are traded on the New York Stock Exchange under the trading symbol “RIG