The Global Mobile Satellite System (GMSS) is a general term referring to the selection of satellite phone providers available to private customers. It is a term analogous to PLMN, referring to wireless telephony (cellular) carriers, and PSTN, referring to traditional wire-based telephony.
As of 2008, the allocated GMSS carriers are:
In 1996, the ITU introduced country code +881 for direct international dialing of phones on a GMSS provider. (Inmarsat had already been allocated country codes +870 - +874.) The next digit following the country code is allocated (two at a time) to a particular GMSS carrier:
| Carrier | GMSS codes |
|---|---|
| ICO | +881 0 +881 1 |
| Ellipso | +881 2 +881 3 |
| spare | +881 4 +881 5 |
| Iridium | +881 6 +881 7 |
| Globalstar | +881 8 +881 9 |
Inmarsat is a satellite-based communications provider, but it is primarily a maritime service and is not generally considered part of the GMSS.
Globalstar usually allocates subscribers with a local number in the country they are based rather than using their GMSS country code.
Iridium also uses an Arizona-based access number to call Iridium phones for those unwilling or unable to call the usually expensive GMSS number directly.
Thuraya has been assigned +882-16 which is part of the +882 country code.