46 CFR § 10.221 - Citizenship.
(a)
(1) MMCs with officer Endorsements. Only individuals with valid U.S. citizenship may apply for officer endorsements, except individuals applying for endorsements as operators of uninspected passenger vessels authorizing service on undocumented vessels in accordance with § 11.201(d) of this subchapter.
(2) All other MMCs. All other applicants, except as noted in § 12.809 of this subchapter, must be either:
(i) A citizen of the United States;
(ii) An alien, as defined under section 101(a)(3) of the Immigration and Nationality Act (8 U.S.C. 1101 et seq.) (the Act), who is lawfully admitted to the United States for permanent residence, as defined by section 101(a)(20) of the Act.; or
(iii) A foreign national who is enrolled in the United States Merchant Marine Academy (USMMA).
(b) Proof of citizenship or alien status must be submitted to the Transportation Security Administration (TSA) with the applicant's TWIC application in accordance with 49 CFR 1572.17(a)(11).
(c) TSA and the Coast Guard may reject any evidence of citizenship that is not believed to be authentic. Acceptable evidence of citizenship may be an original or a copy certified as true by the agency responsible for issuing the document of the following:
(1) If the individual is applying for an officer endorsement (with the exception of those applying for an MMC endorsed only as Operator of an Uninspected Passenger Vehicle (OUPV) of an undocumented vessel), the individual must provide an original of any one of the following documents:
(i) Certified copy of a birth certificate, issued by a State, county, municipality or outlying possession of the U.S. bearing an official seal;
(ii) U.S. passport (expired or unexpired);
(iii) Certificate of Citizenship issued by U.S. Citizenship and Immigration Services or the Immigration and Naturalization Service;
(iv) Certificate of Naturalization issued by U.S. Citizenship and Immigration Services or the Immigration and Naturalization Service; or
(v) Merchant mariner's document issued by the Coast Guard after February 3, 2003, that shows that the holder is a citizen of the United States.
(2) If the individual is applying for a rating endorsement and they hold one of the documents listed in paragraph (c)(1)(i) through (v) of this section, these documents are also acceptable as evidence of citizenship. If the individual does not hold any one of those documents listed in paragraph (c)(1)(i) through (v), the individual must provide an original unexpired foreign passport and an original of any one of the following documents:
(i) Permanent resident card (form I-551) issued by U.S. Citizenship and Immigration Services bearing the certification that the alien was admitted to the United States as an immigrant,
(ii) A declaration of intention to become a citizen of the United States issued by a naturalization court; or
(iii) A certificate issued by the consular representative of the country of which the alien is a citizen or subject.
(3) If the individual is the holder of or applying for a rating endorsement and the individual does not hold any of the documents listed in paragraphs (c)(1) or (2) of this section, proof of enrollment in the United States Merchant Marine Academy (USMMA) in the form of an original letter from the USMMA, signed by the Superintendent attesting to the individual's enrollment along with an unexpired foreign passport issued by the government of the country in which the alien is a citizen or subject, with a valid U.S. visa affixed to the passport, will be acceptable evidence of lawful status in the United States.
(4) If the individual is applying for an MMC endorsed only as OUPV of an undocumented vessel, the individual must provide an original of any one of the documents enumerated in paragraphs (c)(1)(i) through (v) or (c)(2)(i) or (ii) of this section, or proof of acceptable alien status as provided in 49 CFR 1572.105.