The company has installed eight 3G base stations along the route to Everest base camp.
The wireless network could help thousands of tourists who visit Mount Everest every year, Ncell claims.
Climbers and trekkers in the Everest region have so far relied on satellite phones and a voice-only mobile network.
Ncell, which is owned by the Swedish company TeliaSonera, says its highest 3G base station is near Everest base camp at 5,200 metres (17,000 ft).
The coverage would reach the summit of the world’s highest mountain, company head Pasi Koistinen, said.
The 3G network will help climbers and trekkers stay in touch with their families and trip organisers, Mr Koistinen said.
It will also enable them to receive weather reports and safety information while they are climbing.