46 CFR 10.233: Obligations of Merchant Mariner Credential holders

Last reviewed: October 14, 2026

This section sets duties for the holder of a Merchant Mariner Credential. The holder may not voluntarily part with the credential or place it beyond personal control, except as required by regulation or as necessary to safeguard it. The holder must report a loss in writing and return invalid or expired credentials to the Coast Guard.

Applies toThe holder of a Merchant Mariner Credential.

What it says

  1. A credential holder may not voluntarily part with the credential or place it beyond their personal control by pledging or depositing it with any other person, except as required by regulation or as necessary to safeguard the credential.

    46 CFR 10.233(a)“may not voluntarily part with it or place it beyond their personal control by pledging or depositing it with any other person, except as required by regulation or as necessary to safeguard the credential.”

  2. If the holder violates this section, the Coast Guard may pursue suspension or revocation of the MMC under part 5 of this chapter.

    46 CFR 10.233(a)“the Coast Guard may pursue suspension or revocation of the MMC under the provisions of part 5 of this chapter.”

  3. A mariner who loses a credential must immediately report the loss to the Coast Guard.

    46 CFR 10.233(b)“Whenever a mariner loses a credential, they must immediately report the loss to the Coast Guard.”

  4. The loss report must be in writing, be provided in a manner the Coast Guard specifies, and give the facts incident to the loss.

    46 CFR 10.233(b)“The report must be made in writing and provided in a manner specified by the Coast Guard, giving the facts incident to its loss.”

  5. Invalid or expired credentials must be returned to the Coast Guard.

    46 CFR 10.233(c)“Invalid or expired credentials must be returned to the Coast Guard.”

  6. Upon written request, the Coast Guard will return the cancelled credential to the mariner.

    46 CFR 10.233(c)“Upon written request, the Coast Guard will return the cancelled credential to the mariner.”

Common questions

Can I give my mariner credential to someone to hold?

No, a holder may not voluntarily part with the credential or pledge or deposit it with another person. The exceptions are when regulation requires it or when it is necessary to safeguard the credential.

“may not voluntarily part with it or place it beyond their personal control by pledging or depositing it with any other person, except as required by regulation or as necessary to safeguard the credential.”

What must I do if I lose my MMC?

You must report the loss to the Coast Guard immediately. The report must be in writing and give the facts incident to the loss.

“The report must be made in writing and provided in a manner specified by the Coast Guard, giving the facts incident to its loss.”

What happens to an expired credential?

Invalid or expired credentials must be returned to the Coast Guard. On written request, the Coast Guard will return the cancelled credential to the mariner.

“Upon written request, the Coast Guard will return the cancelled credential to the mariner.”

The text of 46 CFR 10.233

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

Obligations of the holder of a Merchant Mariner Credential

(a) The holder of a credential may not voluntarily part with it or place it beyond their personal control by pledging or depositing it with any other person, except as required by regulation or as necessary to safeguard the credential. If the holder violates this section, the Coast Guard may pursue suspension or revocation of the MMC under the provisions of part 5 of this chapter.

(b) Whenever a mariner loses a credential, they must immediately report the loss to the Coast Guard. The report must be made in writing and provided in a manner specified by the Coast Guard, giving the facts incident to its loss.

(c) Invalid or expired credentials must be returned to the Coast Guard. Upon written request, the Coast Guard will return the cancelled credential to the mariner.

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.