Radio License for Boaters
The Telecommunications Act of 1996 permits recreational boaters to have and use a VHF marine radio, EPIRB, and marine radar without having an FCC ship station license. Boaters traveling on international voyages, having an HF single sideband radiotelephone or marine satellite terminal, or required to carry a marine radio under any other regulation must still carry an FCC ship station license.
(The following are excerpts taken from FCC form 506.)
You only need to apply for a license if you are required by law or treaty to carry a radio on your vessel; your vessel travels to foreign ports or transmits radio communications to foreign stations; or you use marine radio equipment on board your vessel other than VHF radios, EPIRBs, and radar.