Iridium, Inmarsat or Thuraya
Once you are out of the reach of a terrestrial internet connection you will have to revert to a satellite link to keep you connected.
The first option for satellite internet at sea are the solutions provided by Iridium, Inmarsat and Thuraya. These systems were designed for use in remote places and each has reasonable coverage at sea, with Iridium providing service even in high latitudes.
The hardware is relatively inexpensive between $5,000 and $20,000 and handheld units, which are getting better at maintaining connections, can be bought for less than a $1000.
While the hardware is “cheap”, the per-minute cost of connectivity is quite expensive with rates measured per megabyte transferred. The slow data rates combined with high connection costs means this solution is not good for doing much beyond downloading text-only emails.
Iridium are the longest running provider of satellite phones and network. They have “truly global coverage” and are the only provider that covers the Arctic, Antarctica and both poles.
Inmarsat Fleetbroadband covers most of the globe except for the top and bottom i.e. Arctic and Antarctica. Unlike Iridium, they use just a couple of geostationary satellites with a much higher orbit which means calls are dropped less often and less subject to being blocked by tall objects.
FleetBroadband gives you simultaneous voice and data capability – all via a single terminal - and can be rapidly deployed across your entire fleet and as a standard IP service
You can choose between a standard, contended IP service and guaranteed data rates on demand. Three types of terminals are available, each offering different performance capabilities.
FleetBroadband uses compact below-deck terminals and stabilized, directional antennas ranging in diameter from 27 cm to 68 cm to deliver optimal maritime connectivity.
Thuraya have a similar geostationary network set up to Inmarsat. Thuraya phones tend to be smaller, lighter and with more features like colour screens, the ability to use normal GSM SIM cards, multi-page text messaging and faster data transfer. Their satellite coverage is regional however so you should check whether it covers where you want to go.