Does GPS work without internet?
Updated 5 August 2026
Short answer: yes. GPS is satellite positioning and it does not need mobile data, Wi-Fi, or a signal of any kind. What stops working offline is the map around your position — and that is a problem you solve before you walk into the forest, not after.
Why GPS works with no signal at all
GPS satellites broadcast, one way, downwards. Your phone listens; it never talks back and never asks a server for permission. Thirty-odd satellites circle the planet, your phone hears four or more of them, compares how long each signal took to arrive, and works out where it is standing. Nothing in that exchange touches the internet.
This is why a phone in airplane mode, deep in a forest, with no bars at all, still knows its coordinates to within a few metres.
So what actually breaks offline
Everything that is drawn around your position:
- Map tiles. The picture of the terrain is downloaded in pieces as you scroll. No connection means no new pieces — you get grey squares with a blue dot in the middle.
- Search. Looking up a place by name asks a server. Offline it returns nothing.
- Route planning on most apps, along with live traffic and anything social.
- Assisted GPS (A-GPS). Normally your phone downloads a small hint file — roughly where the satellites are right now — which lets it find its position in seconds. Without it, a cold start can take one to five minutes of standing still under open sky.
That last one is why GPS sometimes feels broken offline. It is not broken; it is starting from scratch and it needs a moment.
Set your phone up before you lose reception
Do this at home, on Wi-Fi, the evening before:
- Download the map area (which app to use). In Google Maps: search the area → tap the name → Download offline map. Apple Maps has offline areas too since iOS 17. A forest-sized area is usually 30–80 MB.
- Open the app once in the parking area while you still have a bar or two. That fetches the A-GPS hints and gets your first fix instantly instead of after five minutes.
- Check that location stays on. Battery savers on some Android phones throttle GPS in the background. Whitelist the app you intend to rely on.
- Charge to full, carry a power bank. Continuous GPS recording costs roughly 5–10% of battery an hour, more in cold weather.
Airplane mode is your friend, not your enemy
In an area with weak reception, the phone burns battery hunting for a tower it cannot reach. Turning on airplane mode stops that hunt — and GPS keeps working, because reception was never part of it. On iPhone you may need to re-enable Location Services after switching; on Android, GPS stays on by default.
The trade-off is real, so be deliberate: in airplane mode you cannot call for help. If you are alone, keep the phone connected and accept the battery cost, or switch back on every hour to check for a signal.
A blue dot on a grey square is not navigation
Here is the gap most people discover too late. You have coordinates. You may even have a downloaded map. But in a forest, one patch of trees looks like every other patch of trees, and a map without paths cannot tell you which way is back.
What actually gets you out is the thing you recorded on the way in: the point where you left the road, and the line you walked from it. That is a decision you make before the walk, not during it — see how to mark your entry point.
Quick answers
Does GPS use data? No. Positioning is free and offline. Maps use data; the position does not.
Does GPS work in airplane mode? Yes, on both iPhone and Android.
Does it work without a SIM card? Yes. A phone with no SIM at all is still a working GPS receiver.
Why is my position jumping around? Dense canopy, wet leaves, and steep valleys scatter the signal. Standing still for thirty seconds usually settles it.