Two hours out of any road-head in Nepal your phone will, at some point, show a single bar and then nothing at all. Coverage from NTC and Ncell reaches surprisingly far into the main trekking valleys, but it comes and goes with every ridge, and side valleys and high passes are often silent for days. An app that needs the internet to show you the map is a beautiful brick up there.
GPS does not need a signal
This is the part many people don't realise: your phone's location comes from satellites, not from the mobile network. GPS works in airplane mode, at 5,000 m, in a country with no towers at all. What needs the internet is the map underneath your position — the trails, contours, villages and rivers — and that is the piece you must download before you go.
What to download before you leave Kathmandu
- The map for the whole region you'll trek in, not just the first day's section
- The route itself, with its elevation profile and key points (villages, passes, junctions)
- Any side trips or escape routes you might take — the acclimatisation hill, the road-head you'd retreat to
- Do it on hotel Wi-Fi the night before, then open the app once in airplane mode to confirm everything loads
In Trailma, downloading a trail saves the map and route together so navigation, tracking and the elevation profile all work with data switched off.
Keeping a phone alive for two weeks
- Airplane mode all day. Searching for a signal that isn't there is the fastest way to drain a battery.
- Lower the screen brightness and don't keep the map open constantly — check it at junctions.
- Cold kills batteries. Above 4,000 m keep the phone in an inside pocket and sleep with it in your bag.
- Carry a power bank of at least 10,000 mAh. Charging at tea houses is possible but usually paid and often solar-limited.
- Recording your track uses GPS continuously; expect it to cost a few percent per hour and budget for it.
Don't rely on a phone alone
A phone is a superb navigation tool and a fragile one. For remote or high routes, carry a paper map of the region, know the day's plan, and tell someone your itinerary. Trail markers, other trekkers and tea-house owners are the oldest navigation system in the Himalaya and they still work.
Why we built Trailma offline-first
Every design decision in Trailma starts from the assumption that you're standing on a ridge with no signal. Maps, routes, tracking and profiles are stored on the phone; the internet is for syncing when you come back down. Taking your adventure further should never depend on a bar of signal.
