Maritime mobile service (short: MMS | also: maritime mobile radiocommunication service) is – according to Article 1.28 of the International Telecommunication Union´s (ITU) Radio Regulations (RR)– defined as "A mobile service between coast stations and ship stations, or between ship stations, or between associated on-board communication stations; survival craft stations and emergency position-indicating radiobeacon stations may also participate in this service".

This radiocommunication service is classified in accordance with ITU Radio Regulations as follows:

- Maritime mobile service Maritime mobile-satellite service

- Port operations service

- Ship movement service

 

The allocation of radio frequencies is provided according to Article 5 of the ITU Radio Regulations (edition 2012).

In order to improve harmonisation in spectrum utilisation, the majority of service-allocations stipulated in this document were incorporated in national Tables of Frequency Allocations and Utilisations which is with-in the responsibility of the appropriate national administration. The allocation might be primary, secondary, exclusive, and shared.

primary allocation: is indicated by writing in capital letters (see example below)

secondary allocation: is indicated by small letters

exclusive or shared utilization: is within the responsibility of administrations

However, military usage, in bands where there is civil usage, will be in accordance with the ITU Radio Regulations. In NATO countries military utilizations will be in accordance with NATO Joint Civil/Military Frequency Agreement (NJFA).