USCG Merchant Mariner Credential

The Merchant Mariner Credential is the single document issued by the US Coast Guard that combines the former merchant mariner’s document, license, certificate of registry, and STCW endorsement. The MMC certifies a seafarer’s national rating or officer grade and carries the STCW endorsements for international service. It is the US equivalent of the certificate-and-endorsement structure other flag states issue under STCW.