Each country has its own regulatory authority, here in the UK it is the responsibility of the Maritime Coastguard Agency (MCA) and OFCOM.
These notes are for UK registered ships and are only meant as a guide. Non UK registered ships should check with the country of registration.
There are 3 regulations that have to be considered, these are:
Mandatory fitting of radio communication equipment
Depending on the size of the boat will depend whether or not it is mandatory to fit radio equipment. Here in the UK all ships (yachts, boats etc.) are covered by the Merchant Shipping Regulations. For ships less than 13.7 metres (45 feet) only have to comply with SOLAS V regulations. Ships 13.7 metres and over are covered by the Merchant Shipping Regulations which say that "a maritime radio capable of transmitting and receiving, appropriate to the area of operation". Therefore ships of 13.7 metres and over, should have a VHF radio and if off-shore sailing an MF & HF (SSB) radio.
Ship’s Radio Licence
It is an internationally agreed legal requirement to have a ship's radio licence. On the ship's radio licence you will find the ship's international callsign and, if requested, 9 digit MMSI number.
Callsigns and MMSI numbers are internationally allocated. If you know the vessel name, callsign or MMSI number you can find the vessel particulars at the International Telecommunications Union (ITU) web site.
Marine Radio Operator's Certificate of Competence
Regualtions vary around the world and are dependent of the country of registation of the ship, not the citizenship of the radio operator or captain.
In Europe, to operate a marine radio, the radio operator is required to hold a Global Maritime Distress and Safety System (GMDSS) marine radio operator's certificate.
For ships less than 24 metres in length, two types of GMDSS certificates can be obtained.
1. Short Range Certificate which is limited to VHF only operation.
2. Long Range Certificate which allows operation of all (VHF, MF & HF (SSB)) marine radio equipment.
For ships over 24 metres in length, then the radio operator must hold either:
1. Restricted Operator Certificate which is restricted to ships operating in GMDSS Sea Area A1.
2. General Operator Certificate allows operation in ALL GMDSS Sea Areas (A1, A2, A3 & A4) of marine radio equipment (VHF, MF, HF & Inmarsat).
In the US, if the ship is visiting international ports then the marine radio operator must obtain a Restricted Radiotelephone Operator Permit, they do not need to take a test to obtain this permit. For more infomation visit the FCC site at https://www.fcc.gov/wireless/bureau-divisions/mobility-division/ship-radio-stations