Recreational boaters can obtain an MMSI through a number of approved organizations – some even at no charge – but the nominal price, ease, and added benefits of BoatUS's service make it a popular way to register. Which ever way you decide to do it, DO IT NOW! And be sure to properly connect your GPS so that one press of the red button will alert rescuers with your location, leaving you to focus on dealing with your emergency. Don't wait until you really need it!. From a BoatUS press release:

ALEXANDRIA, VA, June 9, 2016 -- In 1991, BoatUS made it easier for recreational boaters on US waters to own a VHF radio by helping to convince Congress to eliminate the $150 annual license requirement and fee. Nine years later, BoatUS began a no-cost DSC-VHF radio Maritime Mobile Service Identity (MMSI) registration service that has become the largest of its kind. Now, BoatUS offers an easy online MMSI registration for $25 that makes obtaining an MMSI number simple, adds an extra layer of safety by partnering with the US Coast Guard to share information, and offers valuable boater benefits. This registration fee includes complimentary BoatUS membership.

“Because our on water dispatch centers never close, BoatUS can help expedite a US Coast Guard response at any hour and provide boat and emergency contact information,” said BoatUS President Margaret Podlich. “It’s about giving rescuers descriptive information as quickly as possible to improve the odds of a successful rescue.” A recently signed Memorandum of Understanding with the US Coast Guard cements the relationship.

Boaters often refer to an MMSI number as the boat’s “telephone” number, however the technology and on water advantages go far beyond simply being able to call other boats directly. When properly connected to a chartplotter/GPS, a Digital Selective Calling (DSC) VHF speeds rescuer’s response times by using precise location information. DSC also makes it very simple to trigger a Mayday call with one touch of the red distress button, and the technology works seamlessly with America’s modern, national Rescue-21 system.

Over 150,000 boaters have chosen the BoatUS’ MMSI registration service, which unlike other providers allows easy updating if the boat’s contact, location information changes and offers other convenient features for the boater. “This program is positioned to grow with the ever changing world of DSC and boat owner needs,” added Podlich.

Recreational boaters who operate only in US waters can obtain their MMSI at BoatUS.com/mmsi. For a look at how DSC VHF works, BoatUS offers a free online DSC VHF tutorial at BoatUS.org/dsc.