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MMC (Merchant Mariner Credential)

The official USCG document containing all of a mariner's licenses, endorsements, and ratings.

A Merchant Mariner Credential (MMC) is the single passport-style booklet issued by the USCG National Maritime Center that contains all of a mariner's active federal credentials — captain's license level, tonnage, endorsements, STCW ratings, and any special endorsements (Sail, Towing, Assistance Towing, etc.).

The MMC replaced the legacy paper license/document system in 2009. Every U.S. captain operating commercially must carry a valid MMC with the appropriate endorsement for the vessel and route being operated.

MMCs are renewed every five years with documented recent sea time, a USCG-accepted medical, a drug test, and any continuing-education requirements tied to endorsements like STCW.

Examples

  • A captain's MMC is inspected during a USCG safety boarding to verify endorsements match the vessel.
  • Adding a Sail endorsement to an existing 100-ton Master credential is recorded in the MMC.

Related Terms

USCG Captain's License—A Merchant Mariner Credential issued by the U.S. Coast Guard that authorizes the holder to operate a vessel for hire.STCW—An international convention setting minimum training, certification, and watchkeeping standards for commercial seafarers.OUPV License—USCG license authorizing a captain to operate an Uninspected Passenger Vessel carrying up to six paying passengers.Masters License—A tiered USCG license authorizing a captain to operate an inspected passenger vessel, sized by vessel tonnage.

References

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