46 C.F.R. § 12.02-12 Identity.
Title 46 - Shipping
(a) Each person applying for a merchant mariner's document shall present acceptable proof of identity. Proof of identity shall consist of two current forms of identification, one of which shall contain a photo of the applicant. The Coast Guard may require other identification information reasonably necessary to prove the applicant's identity. (b) The following credentials are acceptable proof of identity: (1) Unexpired U.S. military identification card; (2) Unexpired U.S. driver's license; (3) Unexpired U.S. passport; (4) Unexpired official identification card issued by a federal, State, or local government or by a territory or possession of the U.S. (including a federal employee's identification credential); (5) Unexpired port credential, with photo of the applicant, issued by State or local port authority; (6) Unexpired law enforcement credential, with photo of the applicant; (7) Unexpired merchant mariner's document issued after February 3, 2003; (8) Unexpired foreign passport; or (9) Birth Certificate or Birth Registration, issued by a State, county, municipality or outlying possession of the U.S. [USCG-2003–14500, 69 FR 532, Jan. 6, 2004]
Title 46: Shipping
PART 12—CERTIFICATION OF SEAMEN
Subpart 12.02—General Requirements for Certification
§ 12.02-12 Identity.

