Can you identify mountains without cell signal?

Yes. Your phone's GPS works without cell service, so an identifier app can still name peaks as long as the data it needs is already on the phone. Peak lists are often built in; terrain data sometimes has to be downloaded first. Prepare before you lose signal by opening your app for the area while connected, and carry a map and compass as a backup.

What needs signal and what doesn't

Three things go into naming a mountain on a phone, and they behave differently when you're out of coverage:

So the question isn't whether a mountain app "works offline" but which of those pieces it already has on the phone when you lose coverage.

Before you lose signal: a checklist

1. Open your identifier app at, or for, your destination while you're still connected. Apps that fetch terrain as you go will cache that area. Apps with downloadable regions need the region saved.
2. Download offline maps for the area in your map app.
3. Calibrate the compass while you have a known landmark in view, and note your declination for paper backup.
4. Charge everything and pack a battery. Cold drains phone batteries fast; keep the phone in an inside pocket.
5. Pack the paper. A topographic map and baseplate compass weigh almost nothing. Our map and compass guide covers the method.

How the main apps handle it

Developers describe this differently, so read the listing before a trip. PeakFinder states that it works fully offline worldwide. PeakVisor and some others work from areas you've downloaded. AI photo apps need a connection for every identification. Our app comparison lists each one's approach, and how mountain identifier apps work explains why AR and photo apps differ.

Mountain Identifier: Peaks without signal

Here's exactly what works when you're out of coverage:

• Peak names, heights and positions: always available. All 687,599 summits are stored on your phone.
• The live camera labels: work anywhere you've opened the app before. They need terrain data, which the app downloads the first time you use it in an area and keeps in the phone's cache. Somewhere you've never used it, with no signal, the live view can't start until it gets terrain data.
• The 3D panorama: the same rule. Previewing a place in the Explore tab while you're connected caches it for later.
• Photo identification and peak profiles: need a connection. Take the photo now and identify it later.
• Your passport, stats and badges: work without signal.

The live view and photo identification are part of the Pro subscription.

The fallback that never runs out

If the phone dies, a bearing and a map still work. Point the compass at the peak, correct for declination, and follow the line on the map to the summit that fits. It's slower, but it's the same geometry the apps use, and it's worth practicing before you need it. Start with the four ways to name a peak if you're new to it.

Frequently asked questions