FleetBroadband is a maritime global satellite internet, telephony, SMS texting and ISDN network for ocean-going vessels using portable domed terminal antennas. These terminal antennas range in size from 291 × 275 mm (The FB150) to the largest 605mm x 630mm (FB500) system, which is capable of 432 kbit/s speeds. These antennas, and corresponding indoor controllers, are used to connect phones and laptop computers from sailing vessels, on any ocean, with the rest of the world. All FleetBroadband antennas require line-of-sight to one of three geosynchronous orbit satellites, so the terminal can be used anywhere, even on land.

The FleetBroadband network was developed by Inmarsat and is composed of three geosynchronous orbiting satellites called I-4 that allow contiguous global coverage, except for the poles. FleetBroadband systems installed on vessels may travel from ocean to ocean without human interaction. If there is line-of sight to one of the three I-4 satellites, then connectivity can be achieved, even in rough rolling seas. Since the FleetBroadband network uses the L band, rain fade is much less of an issue than the larger VSAT Ku band or C Band systems.