MMSI, the Maritime Mobile Service Identity, at BoatUS, has expanded our Frequently Asked Questions (FAQ's) to answer your questions regarding online difficulties, VHF radio questions and general questions about MMSI and how it pertains to your boat.

Questions are grouped by category, so please click on the appropriate question to view the answer. For additional information please contact us at

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General Questions

How can I register to get a free MMSI number?

Several ways: Go to and click on the "MMSI" button to:

  • Register immediately on-line.
  • Down load and print a registration form. Fax or mail the completed form to the BoatUS MMSI program at (703) 461-2840 or mail to MMSI Program 880 S. Pickett St. Alexandria, VA 22304
  • Call (800) 563-1536 to ask questions or to request a registration form.

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What is the quickest way to obtain the Free MMSI number?

Complete the Free online application to receive your MMSI number immediately. Upon completion of registration your MMSI number will appear on a confirmation page. You will also receive 2 separate email confirmations.  One with your MMSI number and login name and the other with your password.  If you do not receive the e-mail, login to your registration and verify your email address.  E-mails may also be caught by a spam filter.  We recommend recording your MMSI# in your radio owner’s manual.

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Is there a fee to receive an MMSI number?

BoatUS, in cooperation with the FCC and the USCG, has agreed to staff and budget this service. BoatUS is offering this registration service free of charge to all recreational boaters as a public service.

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Why has BoatUS elected to absorb the cost of MMSI registration?

MMSI and DSC have the potential to save many lives as the Coast Guard installs their nationwide Rescue 21 communications upgrade. BoatUS wants to insure that recreational boaters have reasonable access to the system. BoatUS has worked on behalf of safe boating from its founding in 1966.

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What will my email address be used for?

Confirmation of your registration will be sent to your email address. You will also be able to retrieve forgotten login and password information from the login page by inputting your email address. Every 18 months we will forward a reminder to update your registration for accuracy and to cancel the registration if the boat has been sold. If there is no e-mail address, or the email provided is undeliverable, this notification will be sent via regular mail.

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How can I obtain a copy of the VHF/DSC Tutorial for teaching purposes?

You can order a free copy of the tutorial from the BoatUS Foundation by going to:

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How can I make changes to my registration?

If any information such as phone numbers, emergency contacts or boat information has changed since you registered, be sure to log in with your previously chosen login & password and choose “Edit Registration” from the menu screen. You may then make changes to your registration as necessary. Please note you would not be able to change Owner or Login Name without assistance from the system manager. (For help call 800-563-1536 or email

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How do I cancel my MMSI account?

Go to and click the Login option. Login using the login and password that you chose when you registered or that was assigned to you. (If you do not remember your login, choose the option to have it e-mailed to you). Once logged in, choose Cancel MMSI Account from the menu screen.

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I have obtained my MMSI number online. Now what?

The radio must have the number programmed into it. Follow the instructions in your owner’s manual regarding how to program the MMSI into your specific radio. Be very careful when programming as most radios only offer one opportunity to reprogram with a new number.

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How can I test to make sure I have programmed the number correctly?

There is no way to test the distress feature without setting off a false alarm to the Coast Guard. Use the DSC function to privately hail another boater’s MMSI number so that they can verify what MMSI came up on their ID. The DSC functions do not work at all until an MMSI is programmed in. If connected to a GPS, the signal will also provide your exact coordinates. TowBoatUS Captains with DSC radios will do a radio check with you if requested.

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Is an FCC VHF license required?

No, recreational boats under 65' operating in U.S. waters no longer require a VHF license.

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I am a recreational boater in the United States but regularly go into Canadian waters. Can I still use the BoatUS MMSI?

While Canada is considered “international waters” which technically calls for an FCC Ship Station License, Canada is not enforcing US regulations. Canada also has de-licensed recreational boaters. Under international treaties to which the US is a party, you are required to have an FCC license to transmit your radio in a foreign port. It is recommended for Mexico, Bahamas and the Caribbean etc. BoatUS and the GMDSS Task Force are working to have the FCC lift the rule for Canada and the Bahamas. Also, the U.S. & Canadian Coast Guard are working together to respond to any distresses in the border waters.

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I am a Canadian boater with a DSC radio. Can I register at BoatUS?

No. The BoatUS MMSI numbers contain a country code and are to be used only for U.S. vessels. Alternatively, you may complete the form to obtain a Free MMSI through Industry Canada by going to:

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What is the difference between obtaining an MMSI from the FCC and obtaining a number from BoatUS?

BoatUS MMSI numbers are coded for recreational vessels cruising in U.S. waters only not otherwise required to be licensed; the registrations are downloaded into the U.S. Coast Guard Search & Rescue Database (MISLE) only. FCC-assigned MMSI numbers are coded for International Waters and go into the International Search & Rescue Database (ITU). In order to be accepted into the ITU database, any FCC assigned MMSI must end in zero. This is why the BoatUS MMSI number cannot be re-used when later applying for an FCC License for international cruising.

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I am voluntarily FCC Licensed but do not have an MMSI number. Can I obtain my MMSI through BoatUS?

Yes. If you are voluntarily licensed and do not plan to cruise in International waters, you may use the BoatUS MMSI number. If your intention is at some point to cruise internationally (ex. Bahamas, Mexico) you will want to contact the FCC instead to have your License modified to include a properly coded MMSI which will go into the International Search & Rescue database. For FCC call (877)480-3201 (Select Option 2 from automated menu).

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I am now required to obtain an FCC License. Should I continue to use the MMSI previously obtained through BoatUS?

No, you will need to complete Schedule B with your FCC License Form 605 in order to have a new MMSI assigned to you by the FCC. The new MMSI will be coded for International waters and the registration will be entered into the International Search & Rescue database.

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