Iridium coverage area: global
Iridium is currently the only network offering pole-to-pole global coverage. This means that you can use Iridium satellite phones nearly anywhere on the planet. (Due to US embargo issues, the service is not available in North Korea.)
Inmarsat coverage area: global (without polar regions)
Globalstar coverage area: America, Europe, Asia (partial), North Africa, Australia
Globalstar covers the Americas, Europe, Australia, parts of Asia and North Africa, as well as some ocean areas. Currently the availability of the serive is limited due to technical issues with the Globalstar satellite constellation – read more about Globalstar’s problems and Globalstar satellite phones.
Thuraya coverage area: Europe, Asia (partial), Australia, Africa (partial)
Thuraya is a local satellite phone service provider, with a growing coverage which currently includes around 30% of the globe. Thuraya covers Europe, Asia, Australia and parts of Africa, as well as some ocean areas.