BoatUS MMSI: Register, Transfer, and Manage Yours
What is a BoatUS MMSI and how do you get one?
A Maritime Mobile Service Identity (MMSI) is a nine-digit number programmed into DSC-capable marine radios and AIS transceivers to uniquely identify your vessel. When you trigger a distress call, the U.S. Coast Guard uses that number to pull your vessel details instantly, including owner contact information, intended route, and onboard equipment.
BoatUS is an FCC-authorized organization that assigns domestic MMSI numbers for recreational vessels. It relays registration data directly to the U.S. Coast Guard’s Search and Rescue database (MISLE), so rescue coordinators can access your information in an emergency.
Eligibility for a BoatUS MMSI:
- Vessel must be used for recreational purposes only
- Under 65 feet in length
- Not legally required to carry a marine radio
- Operates in U.S. waters only — no international travel
If you plan to travel to foreign ports, a BoatUS MMSI is not sufficient. You must obtain an FCC Ship Station License, which includes a separate, internationally valid MMSI number. The Federal Communications Commission manages mandatory and international licensing, while BoatUS handles the voluntary domestic registration track.
BoatUS MMSI registration is free for current BoatUS members. Non-members pay a $25 fee.
How to register your MMSI number with BoatUS
The registration process is straightforward. Complete it before programming your radio — once an MMSI is entered into most DSC radios, it is difficult or impossible to change without manufacturer involvement.
- Confirm eligibility. Verify your vessel meets all four criteria listed above.
- Gather required information. You will need vessel name, hull identification number (HIN), state registration or Coast Guard documentation number, vessel type, length, and owner contact details.
- Apply online or by phone. Visit the BoatUS MMSI application page or call 800-563-1536 to complete the application.
- Pay the fee if applicable. BoatUS members register free. Non-members pay a $25 fee during the application.
- Receive your MMSI. BoatUS issues your nine-digit number and sends a registration certificate confirming active status.
- Program the MMSI into your radio carefully. Enter the number exactly once. Double-check every digit before confirming.
Pro Tip: Most marine radios allow only a limited number of MMSI programming attempts. Exceeding that limit can lock the device, requiring costly factory reprogramming. Verify your number before you touch the radio.
How to transfer an existing BoatUS MMSI number
The MMSI belongs to the vessel, not the owner. When a boat changes hands, the registration must transfer to the new owner so rescue data stays accurate and the previous owner is not liable for a vessel they no longer own.
Steps for the previous owner:
- Log in to your BoatUS account and initiate the MMSI transfer to the new owner.
- Provide the new owner’s contact information as requested.
- Confirm the transfer is complete before the sale closes.
Steps for the new owner:
- Confirm with the seller that the transfer has been initiated.
- Update all vessel and contact details in the BoatUS system.
- If the previous owner is unreachable, contact the BoatUS Help Desk at 800-563-1536 for assistance.
“Since the MMSI number is supposed to follow the vessel, reasonable efforts should be made to give the account to the new owner.” — U.S. Coast Guard Navigation Center
If a transfer cannot be completed and the registration was already canceled, BoatUS can help reclaim or formally cancel the MMSI to maintain database integrity. Canceled registrations remain accessible to the Coast Guard.
Pro Tip: Sellers should never cancel an MMSI registration before completing the transfer. Canceling first creates a gap in the rescue database and complicates the new owner’s ability to claim the number.
How to confirm and maintain your BoatUS MMSI registration
There is no public U.S. Coast Guard database where boaters can independently verify their MMSI status. Confirmation must come directly from BoatUS. Your registration certificate is the primary proof of active status.
Key maintenance practices:
- Keep owner contact information current in your BoatUS account after any address or phone number change
- Update vessel details if the boat is renamed or re-documented
- Review registration accuracy annually, especially before the start of boating season
- Contact BoatUS at 800-563-1536 to resolve discrepancies or request a duplicate certificate
Maintaining accurate MMSI registration is a life-safety issue. Outdated or incorrect data slows Coast Guard response during a real distress event. The FCC also notes that inaccurate MMSI use violates federal rules and can result in enforcement action.
Pro Tip: If you buy a used radio that already has an MMSI programmed in, do not attempt to reprogram it yourself. Contact the manufacturer for the official reset process, which may not require removing the radio from the boat.
Boating safety education from Safeboatingamerica
MMSI registration is one piece of a broader compliance picture. Safeboatingamerica offers state-approved boating safety courses taught by USCG-Licensed Captains and NASBLA-approved instructors, covering emergency procedures, required equipment, and navigation rules across all 50 states.
For boaters who need to satisfy state licensing requirements alongside their MMSI setup, Safeboatingamerica provides online, Zoom, and in-person certification options with same-day certificate availability. Understanding why boating safety education matters puts MMSI registration in its proper context: one part of operating legally and safely on the water.
FAQ
How do I get an MMSI number for my boat?
Apply through BoatUS online or by calling 800-563-1536. BoatUS members register free; non-members pay a $25 fee.
How do I register my MMSI on BoatUS?
Visit the BoatUS MMSI application page, provide your vessel and owner details, and submit payment if you are not a member. BoatUS will issue your nine-digit number and send a registration certificate.
How do I find my MMSI number?
Check your BoatUS registration certificate or log in to your BoatUS account. There is no public Coast Guard lookup tool, so your issuing provider is the only direct source.
Does a BoatUS MMSI work internationally?
No. BoatUS-issued MMSI numbers are valid for U.S. waters only. International travel requires an FCC Ship Station License with a separately issued MMSI.
Key Takeaways
BoatUS MMSI registration is free for BoatUS members and costs $25 for non-members. Registration must stay current to support effective Coast Guard search and rescue.
| Point | Details |
|---|---|
| Eligibility requirements | Vessel must be recreational, under 65 feet, not required to carry a radio, and stay in U.S. waters. |
| Cost structure | Free for BoatUS members; $25 fee for non-members. |
| MMSI belongs to the vessel | Transfer registration to the new owner at sale; contact BoatUS Help Desk at 800-563-1536 if needed. |
| Verification method | No public Coast Guard database exists; confirm status through BoatUS directly using your registration certificate. |
| Safeboatingamerica | Offers state-approved boating safety courses nationwide to help boaters meet licensing and compliance requirements alongside MMSI registration. |