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MMSI Frequently Asked Questions (FAQ)

1. How do I verify that the USCG has my MMSI number? You currently cannot. If you can verify that the provider (FCC, BOAT US, US Power Squadron, Shine Micro or Sea Tow) has accurate registration, then the USCG can access that information. NOTE: You can get a certificate when you obtain your MMSI from a provider.

2. The used radio I bought already has an MMSI and I cannot contact the original owner to have its registration transferred. (Or, the radio’s MMSI is incorrect and I was told to correct it) You must contact the manufacturer about the MMSI reset process. It may be possible to do this without having to remove the radio from the boat.

3. If an MMSI is obtained from Boat US, Shine Micro or Power Squadron, is the MMSI and vessel information available to agencies and Coast Guard groups outside of the USA? No. Only MMSIs issued by the FCC for vessels travelling internationally are available to agencies and Coast Guard groups outside the USA. In an emergency, foreign rescue coordination centers would need to call US Coast Guard rescue coordination centers to obtain vessel information from MMSIs assigned in this manner.

4. How do I obtain a MMSI? By applying for one, see our MMSI page for further guidance.

5. My boat/radio has already been sold and I now realize I should have first transferred/cancelled my MMSI. How can I fix things now? Attempt to contact the buyer to arrange for transferring the MMSI registration. Since the MMSI number is supposed to follow the vessel, reasonable efforts should be made to give the account to the new owner; you can also contact the Help Desk of your service agent for guidance. However, if unsuccessful, update your MMSI registration to note the circumstance, and then cancel the registration. Cancelled registrations remain accessible to the Coast Guard.

6. How can I recover my MMSI so it can be transferred? I sold the boat and prematurely inactivated my registration. To recover your MMSI, contact the Help Desk of the service agent that issued the MMSI and they will assist.

  •  If your vessel is registered with Boat US, Shine Micro, or Power Squadron, please reach out to your respective registration agent to assist in facilitating the process.
  •  If your vessel is registered with the FCC, you may contact the FCC Help Desk for further assistance. Because FCC-issued MMSIs are linked to ship station licenses, the best option for transferring your MMSI to a new owner may vary depending upon your situation. Please visit the FCC Ship Radio Station Licensing page to learn more.

Otherwise, you must contact the purchaser and instruct them to have the radio’s MMSI reset in accordance with the manufacturer’s processes.

7. Why can’t MMSIs be handled like EPIRB identities, encoded into the radio or AIS by manufacturers and registered by a third party?

  • MMSIs used by ships are required internationally to be assigned and registered under the ship’s individual radio station license.  Since every country has long been required to administer radio station licenses anyway, the costs of establishing and administering a new database for MMSIs can thus be avoided.
  • In 1996, the FCC permitted users on ships not required to carry radios, such as recreational boaters, to operate maritime radios without an individual radio station license, but to instead be “licensed by rule”.  License-by-rule MMSI providers were established as an alternative to the requirement that MMSIs be issued under the ship’s individual radio station license.  License-by-rule assignments are unique to the United States. 

8.  I am just a casual sailor and I want to get a handheld radio for emergencies. I do not own a boat, but I would like to be able to use DSC-enabled radio to help the Coast Guard get to me quicker on the boats that I rent, if ever there was a problem.

  • MMSIs for VHF handhelds not intended for dedicated use on any particular boat, and not intended for commercial ships, can be obtained from Shine Micro.  Make sure you select VHF Handheld MMSIs before purchasing.  See also the MMSIs for VHF Handhelds webpage.

9.  I just bought a boat and updated its MMSI registration.  Why does the AIS data display the old boat name? Boat name and related information broadcast by AIS is programmed into the AIS radio.  The AIS radio itself must be reprogrammed when used on a different boat.  Boat information included in the MMSI registration is part of the MMSI database and is not broadcast.  Registration information is available to Coast Guard for use in a distress.

10.  How do I register my AIS? See the Coast Guard’s AIS FAQ How do I register, encode, install, verify my AIS or, obtain or update an MMSI?

11.  Why is it so difficult to reset own-ship MMSI? International agreements specify that once stored, it should only be possible for an authorized user to change the MMSI with cooperation from the manufacturer.

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