Who it's for
Runners, walkers, and the people who worry about them
Twenty miles into a solo training loop, phone in the vest, screen off. Trail Signal taps your shoulder: last signal for the next 4 km — message home now. Alert timings use your actual moving pace, whether that's 4 km/h or 12.
A full day above the valley, where coverage comes and goes with every col. Know which summits have signal and which descents don't — and exactly where it comes back if you need it.
Silence doesn't mean trouble — usually it just means a hill is in the way. Trail Signal is built so the person out there gets warned in time to send the "all fine" message before the gap, not after it.
The flagship
Dead-zone alerts that arrive in time to act
Not a coverage map you have to remember to check — an early-warning system that watches the trail ahead while you move.
🔭 Warned before, not after
Following a route — or just moving in a direction — Trail Signal scans the coverage ahead and alerts ~400 m before predicted signal loss, with how long the gap lasts and where signal returns. Time to send the message, make the call, drop the pin.
🔒 Works with the screen off
Alerts arrive as notifications while the phone rides in a pocket or race vest, and the lock screen always shows the current answer: "next dead zone in 1.8 km."
🧠 Learns your phone
Official predictions run optimistic in the hills. Trail Signal compares them against what your handset actually measures and corrects — per network, remembered between outings.
📉 Live signal watch
Measured from the phone itself: fading, weakening fast, lost (with the distance until it returns), returning, restored. Miles or kilometres — with time estimates from your own pace.
Plan ahead
The signal picture, before you leave the car park
Import a GPX from OS Maps, Komoot, Strava, Garmin — or turn any track you've recorded into a route and follow it again — and get the verdict in seconds: every dead zone counted, the longest gap and where it bites, the patchy stretches measured. Recce a race route and know which support-crew gaps have zero coverage.
Real output, not a mock-up: the app's Signal Report for the Ben Lawers route — that 400 m gap at the 4.4 km mark is the white summit zone in the map at the top of this page, quantified before you've laced your shoes.
Same glen, different network, different day out. Coverage in the hills varies enormously between EE, Three, O2 and Vodafone — filter everything to the SIM in your pocket, or compare before you choose whose phone leads the run.
🗺️ Four layers of truth
Ofcom's official predictions, Ofcom's drive-test measurements, real readings contributed by other runners and walkers, and an inferred map of 114,000+ mast sites — each labelled for what it is: predicted vs measured.
📡 Mast sites, validated
Every inferred mast is checked with line-of-sight raycasting against terrain data and scored for confidence — so you can see which hillside the signal is actually coming from.
🧭 Honest about limits
Predictions are treated as predictions. Measured data is marked as measured. Every alert says which it came from. That honesty is the product.
The map
A serious UK mountain map — that works offline
- Full topographic detail — OS contours, hillshade, 3D terrain, crags and summits that stay visible as you zoom
- Rights of way in legal colours — footpath, bridleway, restricted byway, byway — distinct from what's physically on the ground
- Offline downloads — grab your route's corridor over Wi-Fi; the whole map, coverage layers included, works with zero bars
- A complete map key — every colour, line and texture explained, with tap-to-zoom symbols
- Compass facing arrow — the map shows the way you're actually facing, standing still
Record & contribute
Every mile makes the map better
Your track, coloured by signal
Record with GPS and live signal measurement running together — see exactly where the bars died on the climb. Garmin-grade GPS filtering tuned on real running data, background recording that survives a full day out, clean GPX export. And if you choose, your anonymised readings (snapped to a 50 m grid — no identity, no timestamps) join the Community Signal layer: the only measured, boots-on-the-ground coverage map of the UK hills. The more people run and walk, the truer it gets.
Everything is free while we're in beta. When the beta ends, Premium features become a paid subscription (around £19.99 a year) — with at least 30 days' notice in the app. Recording, contributing, and the community map stay free forever. Founding Contributors — share 25 km of signal data during the beta — get their first year of Premium free.
On the roadmap
Where Trail Signal is going
Planned during the beta — in build order. No dates promised; nothing ships until it's real.
Watch my walk safety
A live link for someone at home that understands signal: "entering a predicted 1.2 km dead zone — expect them back online around 15:40. Don't worry yet." With an overdue alarm if you don't reappear when the prediction says you should.
Nearest signal safety
One tap, even offline: "Signal ~600 m north-east — up the ridge." Mountain rescue's first advice is to get to signal; Trail Signal will point at it.
Satellite sky-view planned
Satellite messaging is arriving on phones — but it needs open sky, and it fails in exactly the gorges and forests where phone signal dies too. Trail Signal will model the terrain and say, for every dead zone: "satellite likely works here" — or "this valley: nothing works, plan accordingly."
Signal reports on the web planned
A shareable page for any route — "EE: 71% covered, two dead zones totalling 2.1 km" — to drop straight into the group chat when you're planning the weekend.