MMSI

Maritime Mobile Service Identity

What is an MMSI?

The Maritime Mobile Service Identity is a unique nine digit number that identifies transmitted signals within the GMDSS system. It functions like a telephone number for the devices on your boat.

The MMSI is assigned to a vessel, and the same MMSI is programmed into all shipboard equipment that transmits and receives digital signals, including VHF radio, medium and high frequency radios, AIS (Automatic Identification System), and INMARSAT satellite terminals. There is an important exception: the EPIRB (Emergency Position Indicating Radio Beacon), which must be registered separately from this site through the NOAA web site.

MMSIs available through USPS are for use by non-compulsory (voluntary) vessels that boat within US domestic waters only.

Reference: USCG Maritime Mobile Service Identity (MMSI) website

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