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About MMSI

What is an MMSI

MMSI or Maritime Mobile Service Identity is a unique nine-digit number identifying your vessel.

Who issues MMSI?

If your recreational vessel will be traveling outside of US domestic waters (including Canada, Mexico and the Bahamas), you will need an MMSI assigned by the FCC.

Under the terms of international treaty, the FCC assigns MMSI to commercial and recreational US-flagged vessels participating in the Global Maritime Distress and Safety System (GMDSS). The FCC assigns MMSIs in accordance with the International Telecommunication Union (ITU) Radio Regulations and periodically notifies the ITU of assignments made to vessels traveling or communicating internationally.

If your recreational vessel will not travel outside of US domestic waters, it does not require an FCC-issued license. You may obtain an MMSI by contacting either BoatUS or United States Power Squadrons.

If your vessel requires licensing by the FCC after you have obtained an MMSI number from BoatUS, Sea Tow Service, or United States Power Squadrons, that MMSI number cannot be used during the application/licensing process when you file with the FCC. MMSI numbers issued by other authorized entities are valid only for ship stations that do not have FCC-issued licenses. The FCC will issue you a new MMSI number.

How is an MMSI used?

MMSI are programmed into marine radio equipment to provide

  • a unique, internationally standardized number for contacting a vessel in cases of distress or safety, regardless of the radio system involved
  • a common method for authorities to gain useful information concerning a distress incident
  • a common number for billing and settlement of accounts for public correspondence.

Upon receiving a distress alert containing an MMSI, authorities such as the U.S. Coast Guard may use the MMSI to find out background information about the vessel (e.g., owner's name, intended route, and other radio equipment on board) and to help determine whether the alert is false. Thus, an accurate MMSI database can help to protect lives and property at sea by reducing the time it takes to locate vessels in distress.  

Do I need an MMSI?

The FCC rules as well as the ITU Radio Regulations require vessel owners to obtain an MMSI prior to using Class A or Class B AIS, a digital selective calling (DSC) radio or an INMARSAT ship earth station.

To use an AIS transponder, must the vessel have an MMSI?

Yes. Class B AIS transponders will not function if an MMSI number has not been programed into the transponder's system. FCC regulations require Class B AIS units to be programmed with vessel information before shipping to US addresses.Milltech Marine provides this service free of charge.

Don't remember your FCC license information or MMSI?

Go to the FCC License Search to search by Call Sign, MMSI or Name

How do I obtain an FCC-issued MMSI?

Recreational users voyaging outside of US waters need to apply for an "SA - Ship Recreational or Voluntarily Equipped" license. There are several steps:

ONE: Go here to register online with the FCC and receive an FCC Registration Number (FRN).

An FRN is a 10-digit number that is assigned to a business or individual registering with the FCC. This unique FRN is used to identify the registrant's business dealings with the FCC and will be used during the licensing process.

Registering online is the fastest way to receive your FRN. You will receive your FRN immediately after submitting your registration information

TWO: Once you have a FRN, login here.

THREE: After logging in, go here to apply for the SA license. Follow the steps shown. 

NOTE: The FCC currently charges $200+ for a ten year SA ship station license.

Once you have completed the license application, it takes about 2 days for the FCC to issue the license. Your license will include a call sign and MMSI for your vessel. You can check back here once you have completed the application and search for your license using your FRN, vessel name or your name.

Once you have your license, complete our Online Form for Class B Programming with all of your information. Note, we do not need a copy of your FCC license as we check those online ourselves before we program your transponder.

Federal users can obtain MMSI assignments from their agency radio spectrum management office in accordance with Section 6.6 of the NTIA Manual.

US Coast Guard users operating DSC or AIS equipment under official orders can obtain an MMSI through Commandant (CG-652) in accordance with Commandant Instruction M2000.3D, Section 11.D.

U.S. Coast Auxiliary surface vessel operators should request assignment of MMSIs using the same method as for a U.S. Non-Federal user. Obtaining MMSIs for DSC-equipped VHF Handhelds

What do the numbers in an MMSI mean?

All ship MMSIs use the format MIDXXXXXX where in the first three digits represent the Maritime Identification Digits (MIDs are three digit identifiers ranging from 201 to 775 denoting the administration (country) or geographical area of the administration responsible for the ship station so identified. See the ITU Table of Maritime Identification Digits. Ships ) and X is any figure from 0 to 9.

Note: Ships transmitting with an MMSI not starting with the digits 201-775 are likely doing so improperly, and may be subject to FCC or USCG enforcement action.

Other MMSI include:

Groups of Ships Group ship station call identities for calling simultaneously more than one ship use the format 01M2I3D4X5X6X7X8X9 , where the first figure is zero and X is any figure from 0 to 9. The MID represents only the territory or geographical area of the administration assigning the group ship station call identity and does not prevent group calls to fleets containing more than one ship nationality. The U.S. Coast Guard group ship station call identity is 036699999.

Coast Radio Stations (Base Stations) All coast or base stations use the format 0102M3I4D5X6X7X8X9,where the digits 3, 4 and 5 represent the MID and X is any figure from 0 to 9. Groups of coast radio stations use the same format. The combination 0102M3I4D506070809 is used to address all 00MIDXXXX stations within the administration. The combination 010293949506070809 is used to address all VHF 00XXXXXXX stations worldwide. These two special combinations are not used in the United States. The U.S. Coast Guard group coast station identity is 003669999.

Search and Rescue Aircraft AIS and DSC equipment used on search and rescue aircraft use the format 111213M4I5D6X7X8X9 where the digits 4, 5 and 6 represent the MID and X is any figure from 0 to 9. In the United States, these MMSIs are currently only used by the U.S. Coast Guard.

AIS Aids to Navigation (AtoN) AIS used as an aid to navigation uses the format 9192M3I4D5X6X7X8X9 where the digits 3, 4 and 5 represent the MID and X is any figure from 0 to 9. In the United States, these MMSIs are reserved for the federal government.

Craft Associated with a Parent Ship AIS and DSC equipment used on craft associated with a parent ship, such as a launch, uses the format 9182M3I4D5X6X7X8X9 where the digits 3, 4 and 5 represent the MID and X is any figure from 0 to 9. No provision currently exists for using these identities in the United States.

AIS Search and Rescue Transmitter (SART) AIS search and rescue transmitters (SART) use the format 917203X4X5Y6Y7Y8Y9, where the digits 4 and 5 are assigned by the International Association for Marine Electronics Companies (CIRM) and refer to the SART manufacturer, and digits 6, 7, 8 and 9 are sequential digits assigned by the manufacturer identifying the SART.