Despite a difficult topography, the area is suitable for Thuraya phones. The Thuraya satellite is located high above the horizon. The satellite is positioned in the southeast, so far is a cover shade expected only when you climb a mountain on the northwest side. To avoid any coverage gaps due to the topography, you can also take an Iridium phone. Although this could cause more disconnects, you know for sure the next satellite will come up a few minutes later.
Nepal – Inmarsat
Starting in Juli 2017 we got the information from customers that their IsatPhones were not able to connect to the network in some regions. Obviously this is blocked. A registration failed in the region Pokhara and in Chitwan National Park. So we cannot recommend the usage of IsatPhone in Nepal at the moment.