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

General Questions

  • Register on-line at! to receive MMSI immediately.
  • If you are unable to register online due to lack of internet access and email, you may request a registration form by fax, mail or email by contacting the MMSI program at or by phone at 800-563-1536. Allow 4-10 days for processing of mail/fax/email requests. Fax the completed form to the BoatUS MMSI program at 703 461-2840, or mail to MMSI Program 880 S. Pickett St. Alexandria, VA 22304. Email to

Complete the 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 an email confirmation of the assigned MMSI number and a copy of your MMSI certificate to keep with your boats documents. 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.

Yes. There is a $25 fee to register for MMSI through this program; however, the registration fee will be waived for current BoatUS Members.

BoatUS has worked on behalf of safe boating from its founding in 1966. MMSI and DSC-equipped VHF radios have the potential to save many lives through the Coast Guard's nationwide Rescue 21 communications system. AIS (Automated Information System) equipment can prevent collisions by providing information on nearby boats' identities, courses, and speeds. BoatUS wants to ensure that recreational boaters have reasonable access to both systems.

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.

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

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.

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.

If you need to test to see if the DSC feature is working, do not test the red button as this will send out an illegal false alarm and cause an unnecessary rescue response! Instead, you may run a test call to the nationwide Coast Guard MMSI number, 003669999. Enter this number into your radio’s calling memory and select the “Test Call” option from the radio’s list of individual DSC calls, you can then press the “call” or “enter” key. Your radio will silently hail the Coast Guard with a digital signal on channel 70. If everything is working properly, your radio will almost immediately receive the Coast Guard’s acknowledgement of your call, providing assurance that both your radio and the Rescue21 system are operating properly. You must be boating in an area served by Rescue21 to use this test. Alternatively you may also 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.

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

While Canada is considered “international waters” which calls for an FCC Ship Station License, it is our understanding that Canada is not enforcing US regulations. Canada has also de-licensed recreational boaters. That does not mean they can not or will not require it if given reason to do so. If you proceed to operate in the shared waters without license you do so at your own risk. 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.

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 MMSI through Industry Canada by going to:

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.

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).

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.

No. Federal users can obtain MMSI assignments from their agency radio spectrum management office in accordance with Section 6.6 of the NTIA Manual. Official DHS and U.S. Coast Guard users can obtain an MMSI through Commandant Instruction M2000.3D, Section 11.D. U.S. Coast Guard Auxiliary surface vessel operators should request assignment of MMSIs using the same method as for a U.S. Non-Federal user

Online Difficulties

You created a login & password specifically for MMSI when you registered. If you do not recall your MMSI login & password you can retrieve them from the database on the login page.

Your security settings may be too high. You may need to enable cookie support in your browser to use the MMSI application pages. A cookie is a small piece of information that is saved on your computer by a web site.

Go to the login page at and choose “Email address has changed.” Complete the form to verify your registration and login and temporary password will be emailed to your new email address.Be sure to check your spam filter if you do not receive the email.

Login and password are case sensitive and must be input exactly as previously registered. If you are uncertain of your login and password you can go to the login page at and reset your password by entering the email address you registered with. If you are a member of BoatUS and trying to use your logon or member#, it will not work for the MMSI database.

The EPIRB Field has exactly 15 digits. Try backspacing to the beginning of the field as there may be an extra space prior to where you started inputting the number.

No. Registration for EPIRB (Emergency Position-Indicating Radio Beacon) is done through NOAA, NOAA oversees this satellite search and rescue system which is not related to DSC VHF marine radios.

VHF Radio Questions

Yes. If you have 2 fixed mount radios on the same boat you may input the same MMSI number in both radios

If you plan to use the handheld on other boats, you might want a separate MMSI number so that you can update the registration according to which boat it is currently on. If you plan to use it only on one boat, you can use the same MMSI number as the fixed radio.

If the handheld is for Marine use, yes; however you would need to keep the registration updated according to the specifics of which boat it is being used on. Reason being, the USCG could be misled in a distress situation thinking a distress came from a boat other than the one actually involved and could end up dispatching the wrong type of rescue unit or calling the wrong emergency contact in any particular situation. Also, it would be inappropriate to register handheld VHF if the intention is for over land use such as hiking. The Coast Guard will not be the appropriate response for this type of distress. Use of Marine VHF Radios on land is prohibited.

If you already have a valid FCC license, you should contact the FCC to get your MMSI. If the FCC has not assigned one to you already, they can assign one and modify your license to include it. The BoatUS registry is intended for those not licensed or required to be FCC licensed so you should not obtain your MMSI through BoatUS.

Ship station licenses are not transferrable from one boat to another, but the FCC will offer a prorated refund for the years remaining on the ship station license should the owner cancel once the boat has been sold. BoatUS cannot assist with the MMSI transfer process for an FCC assigned MMSI in connection with a ship station license, but if the prior owner of the MMSI has cancelled the ship station license through the FCC, the MMSI can be transferred to the ship station license of the new owner of the vessel and programmed radio by contacting a licensing representative at 1-877-480-3201 (select opt 2 from menu). If the new owner is not required to carry a license but has confirmed the previous owner has cancelled his ship station license, it is safe to input the FCC assigned MMSI into the BoatUS database with the new owner information.

BoatUS has been instructed by the FCC and Coast Guard not to assign MMSI for this type of radio. There is currently no agency foreign or domestic that is authorized to assign MMSI for a dive radio. MMSI is designed for use with vessels licensed by rule. The dive radio does not qualify as it is not associated with any vessel.

NO. Use of Marine VHF Radios on land is prohibited. It would be inappropriate to register a marine use handheld VHF if the intention is for over land use such as hiking. The Coast Guard will not be the appropriate response for this type of distress.

What is MMSI?

Maritime Mobile Service Identity

A unique 9 digit number that is assigned to a DSC radio station or an AIS unit

Digital Selective Calling — which is a new radio technology allowing enhanced distress radio messages to be sent digitally.

Maybe. Radios with DSC capability have been on the U.S. market for nearly a decade. Since 1999, the FCC (Federal Communications Commission) has required new fixed mount models introduced in the U.S. to be equipped with the DSC feature. Minimally, DSC radios are equipped with single-button emergency transmission capability. The earlier SC-101 class radios have been largely replaced by superior Class D DSC radios. Check your Radio Owner's Manual for verification.

Similar to a cell phone number, it is your unique calling number for DSC VHF. It also registers the boat information in the U.S. Coast Guard's national distress database for use in emergency situations. Your MMSI number is transmitted with a DSC call, like “caller ID.”

DSC radios have a one-button emergency transmit button that sends the vessel's unique MMSI number. In addition, if the DSC equipped radio is linked to a GPS or Loran unit, the distress call will include the vessel's position. Should the skipper become incapacitated, the radio will continue sending the mayday. In addition, a DSC equipped vessel with an MMSI number can make a "private" hailing call to another DSC-equipped vessel. Only the vessel being called will receive the hail.

Not completely nationwide yet, until Rescue 21 is declared operational throughout the continental U.S. by 2012 and, later (2011-17)for Alaska, Puerto Rico and Guam. However, Rescue 21 is operational on many coasts, for example, from New York to Florida and around the Gulf Coast to Houston as well as the Pacific Northwest. Commercial ships are required to monitor the DSC-reserved Channel 70 for distress calls and have relayed maydays to the Coast Guard. In an emergency, Channel 16 should be used first. (See implementation map at

You will need to submit the following forms to the FCC via the Universal licensing system online or by downloading and completing the following forms and sending them to the FCC. Please contact the hotline number below for questions and assistance with filing:
FCC Gettysburg, PA 877-480-3201 opt 2 Universal Licensing System (ULS) Hotline, now called "Licensing Support Center" - for questions & personal assistance - to access the following necessary forms, by number Form 160 (FRN) FCC reg # - free - personal ID good for life - for FCC system use only - must have/get one to do business w/ FCC Form 605 - Ship Station License, for boat $215 for 10 yrs ($15 refund of the regulatory fee portion for each remaining year of the term if cancelled prior to expiration) Need following addenda to the Form 605 Sched B gets your vessel an internationally recognized & accessible MMSI - free - use same MMSI with AIS and (generally) all DSC radios onboard Sched E (rrtop)(RR) - permit to use a marine radio $65 - your personal permit, good for life (Note distinction: vessel needs LICENSE; you need PERMIT) Form 1070Y (fee schedule) - just to verify the prices above Form 159 (Remittance Advice form) tells FCC how to allocate funds

No. The Coast Guard has no plans to stop monitoring Channel 16 at any time in the foreseeable future.

Yes, channel 70 is to be used exclusively for DSC.

It is in effect "private hailing" of another vessel whose MMSI number is known to you. Once contact is established between the vessels, they are automatically switched to the preselected "working channel", and the "privacy" ends at that point, meaning that the transmission (conversation) can be heard by any other vessel monitoring that channel.

The first digit or two identifies one of the four kinds of Maritime Mobile Service Identities:

  • Ship station identities
  • Group ship station identities
  • Coast station identities
  • Group coast station identities

For a complete breakdown and explanation of the 3-digit prefixes, visit the following USCG web site:

MMSI as it Pertains to the Boat

The MMSI stays with the radio which it is programmed into.

  • If you sell the boat but keep the radio, you can update with the new boat information in the Edit Registration Screen.
  • If you sell the boat with the radio, you must cancel your MMSI registration to avoid having the distress linked to you and your personal information should the new owner fail to reprogram the radio or request that the MMSI be transferred over to them.
  • If you kept the boat but have traded or replaced the radio which was programmed, you must cancel your MMSI registration for the same reason stated above.
  • If you obtained a second radio to go on board the same boat, you may program the same MMSI number into that radio.

Yes, in fact YOU MUST if you wish the system to work. In a distress situation, it is vital to identify the particular vessel, home port, etc.

If you sell or trade your boat and radio with an MMSI number programmed into it, please be sure to login and CANCEL the MMSI account to make the number available to the new buyer. Once it is canceled we will know it is ok to reassign the number to the new owner should they enquire about it. Do not continue to use the same MMSI number with a new boat & radio as it would still be tied to the one you have sold. Instead, you would need to register for a new MMSI number for any new radio.

If the MMSI number was assigned by BoatUS and the previous owner has closed the account, we can re-register the MMSI number for the new owner. If the previous owner has not closed the account, we will attempt to contact them to verify that they are not still using the number in another radio. If the previous owner cannot be contacted or is still improperly using the MMSI you will need to reprogram the radio with a new number. To check if your MMSI was assigned through BoatUS, Call 1-800-563-1536 and make sure to provide the MMSI number in all correspondence!

Check your owner’s manual for the procedure for obtaining this information from the radio. Tip: If the DSC features are working, then there is a number programmed into it. If you cannot obtain the number from the radio, contact the manufacturer for assistance.

You may re-register your number on the BoatUS website by going to (click on the 3rd option to the left – “Already have a NonBoatUS MMSI”). Input your current MMSI number and proceed with the application process. Upon completion of the registration the system will assign you your FCC MMSI number rather than one from our database.

No, that information applies to someone else. You may contact the FCC to determine whether the previous owner has cancelled the ship station license. If yes, you can request that the MMSI be transferred over to your own ship station license for that vessel. To contact the FCC, call (877) 480-3201 and select option 2 to speak with a licensing representative.

See owner's manual for instructions on how to retrienve number from memory, or try the USCG national group MMSI, 003669999, or place a direct or “private” hail to another MMSI known to you and ask that the originating MMSI (your MMSI) be read back to you from the receiving unit's display screen.

Privacy and Your Radio

BoatUS MMSI data is transferred to the Coast Guard on a weekly basis. Once it is in the Coast Guard's database, BoatUS has no control over what other agencies may have access to that data or how it may be used. In addition, if you are broadcasting your position using an AIS receiver, your movements will be visible to others and anyone can view your track real time using websites like NOAA Ship Tracker and Ship Finder.

The information you provide to obtain an MMSI is transferred to the Coast Guard weekly for inclusion in their MISLE (Marine Information for Safety and Law Enforcement) database. This database can be accessed by Coast Guard watch standers when a distress signal is received so they can get in touch with the emergency contacts to verify the emergency. This database is also accessed by federal, state, and local law enforcement agencies for a variety of law enforcement functions.

The amount of information available about you and your location depends upon which radio function you are using. In summary, no information you did not pass along would be available using the traditional voice functions of the radio. Your MMSI number will be transmitted whenever you use the DSC functions on the radio. Your MMSI and your position will be transmitted if you use the polling, reporting, or distress functions. More details follow.

When you use the analog (non-digital) voice functions on your VHF, no position or identity information is transmitted, so no one could identify your or tell where exactly you are. You can think of it as using a walkie-talkie. Anyone in range can hear your voice, but they only know what you choose to tell them.

If the analog functions on the radio are a walkie-talkie, the digital selective calling (DSC) functions can be compared to a cell phone with the MMSI number being your phone number. Whenever you use the DSC functions on your radio, your MMSI will be transmitted, a sort of caller ID. As with cell phones, most DSC calls occur between two specific radios, so you can only call someone if you have their MMSI and only they would see your MMSI. Unlike a cell phone, when you switch to a working channel and begin talking to the other party, you are back to using the analog function of the radio - back to using a walkie-talkie - and anyone listening to the frequency you have chosen will be able to hear you.

The reporting function on your radio provides your position along with your MMSI number to other vessels. It allows you to let your buddies know where you are fishing, for example. Again, you must “call” those other vessels using their MMSI numbers, and, just as if you were calling them on a cell phone, only their radios would display your reported position and MMSI number.

The polling function on your radio allows you to obtain the position of a specific vessel using their MMSI number. If their radio is operating within transmission range and is hooked up to their GPS, their position will be transmitted back to you. That can be automatic if the radio has been set up for automatic response (the default setting on many radios), or it can require you to manually authorize the response. Conversely, anyone polling your radio can get your position without your sending it manually if you have set up automatic response and your radio is connected to a GPS. The display will show that someone has polled your position, and an alarm will sound; however, the alarm can be turned off or be too quiet to hear. If you do not want your position sent automatically to a polling request, see your owner's manual to determine how to set up your radio so that you have to authorize it manually.

When you use the distress function on your radio, both your MMSI and your position are transmitted along with information you input on the emergency. Any vessel or shore station receiving that transmission would know where you were and be able to identify you through your MMSI. Anyone with access to the Coast Guard MISLE (Marine Information for Safety and Law Enforcement) database could determine your identity from your MMSI. And if you have an MMSI from the FCC (Federal Communications Commission) obtained with a ship station license, in addition to the information being in MISLE, anyone could go online and determine your identity on the FCC Website.

The point of AIS is to make your position known to others. Class A and Class B AIS units transmit your position and any identifying information you have programmed into the AIS unit, including your MMSI. An FCC-issued MMSI can be looked up on the FCC website and all of the vessel and owner information can be determined. Several websites track vessel movements using AIS transmissions (,, etc.) and identify vessels from their MMSIs using the FCC database. BoatUS-registered vessels will appear on those websites with the MMSI number only unless you have provided more information to the websites directly. Whenever you are running a Class A AIS, assume that anyone who wants to can find your location and identity.