Short answer: losing phone signal is not the same as being lost. Your phone finds your location from GPS satellites, which work with no signal at all, so if you saved an offline map before you set off, your position and route are still right there on screen. If you didn't, stop where you are, stay calm, and work back to the last point you were sure of rather than pressing on into the unknown.
The first time your signal drops out in the middle of nowhere, it can feel like the floor has gone. The loading spinner spins, the map greys out, and some quiet part of your brain starts drafting the news headline. Take a breath. This is one of the most normal things that happens outdoors, and it's almost always a non-event. Here's what's actually going on, and what to do about it.
Why losing signal doesn't mean losing your way
Two different things are happening on your phone, and it helps to keep them apart.
There's mobile signal, which your phone uses to make calls and download things. And there's GPS, which works out where you are from satellites overhead. GPS needs no signal, no data and no bars. So even when the map has stopped loading, your phone still knows exactly where you are. There's more on this in do you actually need offline maps for hiking?.
The catch is the map itself. Without signal, your phone can't download a fresh map to show your position against. That's the entire reason offline maps exist, and it's the difference between the next two situations.
If you saved an offline map before you left
Good news: not much has changed. Your saved map is still on your phone, GPS is still placing you on it, and your planned route is still sitting underneath your position. Losing signal has cost you nothing that matters.
Have a quick look to confirm you're still on your line, then carry on. If you have drifted off the route, you'll be able to see it and correct while it's a small nudge rather than a long backtrack. This is the whole case for saving your map before you go, made in a single moment on a hillside.
If you didn't save a map, and the screen's gone blank
This is the situation worth knowing how to handle, because a bit of calm makes all the difference.
Stop walking. The instinct is to push on and hope the path resolves itself, and that's usually how a small wrong turn becomes a long one. Standing still for a minute costs you nothing.
Then take stock. Where were you last certain of your position? How long ago was that, and roughly which direction have you come since? If you can retrace your steps to that last sure point, do it. Known ground beats guesswork every time.
If retracing isn't practical, look for a handrail: a long, obvious feature you can follow that you know leads somewhere, such as a wall, a fence, a stream or a clear track. Following one of these is far safer than striking off across open ground on a hunch. In the same spirit, heading downhill towards a valley, a road or a treeline will often bring you back to something recognisable.
It's also worth moving to higher or more open ground for a moment, because a ridge or a clearing will sometimes catch a bar or two of signal. That can be just enough to reload the map or send a message, even when a call won't connect.
Getting a message out with no signal
If you genuinely need help, a few things are worth knowing.
A text will often get through when a call won't, because it needs far less signal, so try a message to someone even if calls are failing. Moving into open sky, away from dense trees or a steep valley side, gives whatever signal exists a better chance.
Emergency calls are a special case. Calling your local emergency number (999 in the UK, 112 across Europe, 911 in the US) can sometimes connect through any available network rather than only your own provider's, so it's worth trying even when your phone shows no signal. Some recent phones can also send an emergency message via satellite when there's no signal at all, though this depends on your device and country, so it's worth knowing before you set off whether yours can.
None of this is a reason to feel nervous about heading out. It's the same reason you glance at where the exits are on a plane. You'll almost certainly never use it, and it's a calmer walk knowing it's there.
Making it a non-event next time
Nearly all of this comes down to a couple of minutes before you leave.
Save your route and the map around it while you've still got signal, so a dropout becomes something you barely notice. Start with a charged phone and carry a power bank on longer days, since GPS and a lit screen do use battery. Tell someone where you're going and when you expect to be back. And on longer or more remote routes, a paper map and a rough sense of where you are is a reassuring backup that never runs out of charge. There's a fuller run-through of all this in how to plan a walking or running route.
Do that, and losing signal goes back to being what it should be: a bit of quiet, not a bit of drama.
That's what LaceLock is being built for. Save your route and maps for offline before you go, and follow your position live wherever you end up, bars or no bars.