When setting out on a water adventure, it’s essential to ensure that you’re equipped with the necessary tools and knowledge for safe and efficient communication. One such critical element is the Maritime Mobile Service Identity (MMSI). In this article, we’ll explore what MMSI is, why it’s essential, and the steps you need to take to register for one.

What is MMSI?

Maritime Mobile Service Identity (MMSI) is a unique nine-digit number assigned to your vessel’s communication equipment, such as a VHF radio, Automatic Identification System (AIS), or Digital Selective Calling (DSC) system. MMSI serves as a digital identifier that simplifies communication with other boats, maritime rescue services, and coast stations. It also assists in distress calls and enables the transmission of important navigational data.

MMSI capable radio with distress button

Why is MMSI Important?

Having an MMSI is crucial for several reasons:

  • Enhanced Safety
    In case of emergencies, MMSI allows you to send a distress signal with the push of a button, quickly alerting nearby vessels and rescue authorities. The MMSI also provides your boat’s information, including its location, which can expedite the search and rescue process.
  • Streamlined Communication
    MMSI enables direct communication with other vessels through their unique identifiers, eliminating the need for time-consuming voice calls and ensuring faster, more efficient communication.
  • AIS Tracking
    MMSI is essential for the Automatic Identification System (AIS), which helps monitor vessel movements and provides crucial information such as a vessel’s name, course, and speed. This data is invaluable for collision avoidance and navigational safety.

Register for an MMSI

To obtain an MMSI for your vessel, follow these steps:

  1. Determine the appropriate issuing authority
    Depending on your location and the type of vessel, different organizations issue MMSIs. Some are listed below.

    Register with America’s Boating Club: https://www.americasboatingclub.org/ (free)
    Register with BoatUS: https://www.boatus.com/mmsi (free for members)
    Register with the FCC: https://www.fcc.gov/licensing-databases/forms
  2. Gather necessary information
    Before applying, gather essential information about your vessel, such as its make, model, year of manufacture, and hull identification number (HIN). You’ll also need your boat’s radio and communication equipment details.
    We recommend the Standard Horizon HX890 for its excellent features and performance. You can check it out compared to other handheld VHF radios “2023 best handheld VHF radios“.
  3. Complete the application
    Visit the website of your chosen issuing authority, create an account, and complete the online application form. After submitting the required information and documentation, you will receive your MMSI.


Program your MMSI: Once you have received your MMSI, you need to program it into your VHF radio, AIS, or DSC system. Consult your equipment’s user manual for instructions on programming the MMSI.


Having an MMSI is a vital component of responsible boating, as it enhances safety and simplifies communication on the water. By understanding its importance and registering for one, you can ensure a safer and more enjoyable experience for yourself and fellow mariners.

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