46 CFR 10.221: Citizenship requirements for mariner credentials

Last reviewed: October 14, 2026

This section says who may apply for a Merchant Mariner Credential based on citizenship or alien status. Only U.S. citizens may apply for officer endorsements, with an exception for OUPV on undocumented vessels. It also lists the documents accepted as proof.

Applies toApplicants for MMCs with officer endorsements and for all other MMCs, including rating endorsements.

What it says

  1. Only individuals with valid U.S. citizenship may apply for officer endorsements, except those applying for Operator of Uninspected Passenger Vessels (OUPV) endorsements authorizing service on undocumented vessels.

    46 CFR 10.221(a)(1)“Only individuals with valid U.S. citizenship may apply for officer endorsements, except individuals applying for endorsements as Operator of Uninspected Passenger Vessels (OUPV)”
  2. All other applicants, except as noted in § 12.809 of this subchapter, must be a U.S. citizen, a lawfully admitted permanent resident alien, or a foreign national enrolled in the United States Merchant Marine Academy (USMMA).

    46 CFR 10.221(a)(2)“All other applicants, except as noted in § 12.809 of this subchapter, must be either:”
  3. 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).

    46 CFR 10.221(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).”
  4. TSA and the Coast Guard may reject any evidence of citizenship that is not believed to be authentic.

    46 CFR 10.221(c)“TSA and the Coast Guard may reject any evidence of citizenship that is not believed to be authentic.”
  5. An applicant for an officer endorsement, other than one seeking only an OUPV endorsement for an undocumented vessel, must provide an original of any one of the documents listed in paragraph (c)(1)(i) through (v).

    46 CFR 10.221(c)(1)“the individual must provide an original of any one of the following documents:”
  6. A rating endorsement applicant who holds none of the documents in paragraph (c)(1)(i) through (v) must provide an original unexpired foreign passport and an original of one of the documents listed in paragraph (c)(2).

    46 CFR 10.221(c)(2)“the individual must provide an original unexpired foreign passport and an original of any one of the following documents:”
  7. A rating endorsement holder or applicant with none of the documents in paragraphs (c)(1) or (2) may show lawful status with an original USMMA letter signed by the Superintendent and an unexpired foreign passport with a valid U.S. visa affixed.

    46 CFR 10.221(c)(3)“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”

Common questions

Can a non-citizen get an officer endorsement?

No, only individuals with valid U.S. citizenship may apply for officer endorsements. The exception is OUPV endorsements authorizing service on undocumented vessels.

“Only individuals with valid U.S. citizenship may apply for officer endorsements, except individuals applying for endorsements as Operator of Uninspected Passenger Vessels (OUPV)”

Where do I submit proof of citizenship for an MMC?

Proof of citizenship or alien status must be submitted to TSA with the applicant's TWIC application in accordance with 49 CFR 1572.17(a)(11).

“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).”

Is an expired U.S. passport acceptable proof of citizenship for an officer endorsement?

Yes. The text lists a U.S. passport, expired or unexpired, among the documents an officer endorsement applicant may provide in original.

“U.S. passport (expired or unexpired);”

The text of 46 CFR 10.221

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

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 Operator of Uninspected Passenger Vessels (OUPV) 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.

Sections it refers to

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.