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If you’ve got a Garmin VHF radio unit on your boat you need to take the extra step to register your MMSI number. It’s an important safety feature.

What is MMSI and Why is it Important?

An MMSI (Maritime Mobile Service Identity) number is a nine-digit identifier assigned to your vessel. Think of it as a digital fingerprint which allows your boat to be instantly identified in an emergency situation and when you have to make a distress call. The MMSI allows responders to instantly see who you are, what kind of boat you’re on and where you’re calling from. If you’re in an emergency situation, that can be life saving.

But to take advantage of this safety feature, you have to program your VHF radio system with your MMSI number—and before that, you need to register your MMSI number. It just takes a few minutes, and we’ll explain how to do it.

First, register your MMSI number. BoatUS is the most common MMSI issuer for recreational boaters in the US who operate only within domestic waters. Registration is free for BoatUS members and $25 for non-members. Go here to get started.

The process is quick and easy, and you will get your MMSI number almost immediately. Record your number and keep it saved someplace safe and accessible.

Program Your Garmin Radio

Once you register your MMSI number, you need to enter it into your Garmin VHF unit. Garmin models such as the VHF 110, 115, 210, 215, 215AIS, and 315 all include DSC (Digital Selective Calling) functionality.

Here’s how to do it (steps may vary slightly according to your model)

1. Power on your Garmin VHF radio unit.
2. Press MENU and navigate to Setup.
3. Select DSC or MMSI settings.
4. Choose Enter MMSI (or My MMSI)
5. Carefully enter your nine-digit MMSI number.
6. Confirm the entry–Garmin radios typically allow the MMSI to be entered once, then lock it in permanently unless reset by Garmin service. 

Once entered, your radio is now fully DSC-capable.

With your MMSI registered and entered, your radio can now use Digital Selective Calling. The key functions are:

• One-button distress calls.  Pressing the red distress button on the radio sends an automated mayday with your MMSI and current GPS position (if connected to GPS).

• Automated Position Sharing. DSC allows you to “pong” another vessel’s MMSI to exchange positions –helpful for contacting fishing buddies on group trips.

• Improved Emergency Response. Search and rescue agencies receive precise data instantly, reducing response times dramatically.

As you can see, enabling DSC turns your VHF radio into a powerful safety device.

What about AIS?

Some modern VHF radio units include AIS (Automatic Identification System) capabilities. Garmin sells two models with AIS: the VHF 215 AIS and the AIS 800. 

The Garmin VHF 215 AIS is a Class D AIS (Receiver only).  This means you can see other AIS-equipped vessels, but they cannot see you. This unit is lower cost and easier to install, and is good for smaller boats tracking local commercial traffic. Casual inshore boaters often start with a Class D receiver.

The Garmin AIS 800B is a Class B AIS (Transceiver). This unit transmits and receives AIS signals from other boats. It has a higher transmit power, faster position update intervals and allows other boats to see you on their AIS displays. This unit is useful for offshore fishermen, cruisers and commercial operators. 

Paired with DSC features and the right AIS capability, taking the time to register your MMSI number and enter it into your Garmin radio is a small step that will dramatically enhance your boat’s safety and visibility. Your Garmin VHF radio will become one of the most powerful emergency and navigational tools on board.

If you still have questions, please contact Ocean House Marina’s service department. We’ll help you add these important safety features to your boat.