The best walks are rarely the best-connected ones. Head into the Cheviots, mid-Wales or most of the Highlands and the signal bars vanish long before the views do. Offline maps solve that, but the apps are not interchangeable. Some carry official Ordnance Survey detail, some lean on open data; some will hold a full day's navigation on one charge, others will not last the afternoon. What follows is a comparison written for walkers rather than gadget collectors.

Three kinds of "offline"

Before comparing apps, it helps to know what you are actually storing on the phone.

  • Cached tiles. The app saves picture tiles for an area you choose. Excellent fidelity, because you are looking at the real published map, but heavy on storage and slower to redraw.
  • Vector maps. The app draws the map on the device. Files are small, zooming stays crisp, but the detail is only as good as the underlying data.
  • Your GPS receiver. This works with no phone signal at all. It needs a clear view of the sky, not a mast. Switch to airplane mode and you cut battery drain without losing your position.

Whatever you choose, test it at home first: download an area, put the phone in airplane mode, then check that the map still draws at the zoom you would use while walking, that the grid reference matches a paper map, and that the route you planned is stored on the device rather than only in your account.

The apps that matter for UK walking

OS Maps

The benchmark for Great Britain. Explorer 1:25,000 and Landranger 1:50,000 mapping, with rights of way, access land shading, field boundaries and the small print that matters when a path fades into bracken. Offline downloads sit behind a subscription; free accounts are for browsing. The trade-off is weight: raster tiles mean bigger downloads and a thirstier screen, and the interface is functional rather than elegant.

Outdooractive

Absorbed ViewRanger and kept much of its appeal for long-distance walking. Stage-by-stage descriptions, guidebook content and good trail records for routes such as the Coast to Coast or the West Highland Way. Map layers vary by tier, and offline use generally requires a paid plan. If you like reading a route description as well as following a line, it is strong.

Komoot

Built on OpenStreetMap with a genuinely good route planner, sold as one-off regional map packs or a wider bundle rather than a rolling subscription. Routing is sport-specific, so walking, cycling and mountain biking give different results. The caveat: OSM shows public footpaths and bridleways in Britain reasonably well, but without the legal clarity of Ordnance Survey. Use it to plan, not to prove a right of way.

AllTrails

A discovery tool. The library of user-contributed routes, reviews and photos is useful when you want a six-mile loop near a campsite. Offline maps and turn-by-turn alerts need a subscription. Route quality varies, so read recent reviews for erosion, closures or a path that no longer exists.

Gaia GPS and Locus Map

Aimed at people who enjoy layers, GPX imports, custom offline areas and multiple tile sources. Both reward fiddling and punish impatience. Check which UK layers are included on your plan before paying, because official OS mapping is not guaranteed on every platform.

Free and open alternatives

Organic Maps and similar OpenStreetMap-based apps cost nothing, need no account and take up little space. Fine for lowland paths, towns and as a backup. Thin on the detail that matters on open moorland.

Map detail: what you actually see

Scale is not the same as usefulness. A 1:25,000 sheet shows walls, fences, streams and contour lines at ten-metre intervals, which is what lets you judge whether the path runs on the near or far side of a wall. Access land shading matters enormously in England and Wales, where open country can be walked legally and farmland cannot.

An offline map is only as good as the data you downloaded and the area you remembered to cover.

Download a generous margin around your route. Route corridors that end exactly at the car park are a reliable source of trouble.

Battery, storage and cold fingers

Screens drain batteries far faster than GPS. A phone that lasts two days in a pocket can be down to single figures after six or seven hours of continuous navigation on a cold, bright day.

  • Download everything on home wi-fi, then walk in airplane mode.
  • Turn brightness down; use a dark theme after dusk.
  • Keep the phone in an inside pocket. Cold cells lose capacity quickly.
  • Carry a small power bank and a short cable, and keep both warm.
  • Track only when you want the record; continuous logging is the biggest hidden cost.
  • Delete downloaded areas you no longer need. Raster packs for a national park can run to hundreds of megabytes.

What the subscriptions buy

Most apps install free and browse free. Offline storage, premium layers and route tools are where money comes in. Patterns are broadly:

  1. Free tier: online maps, basic tracking, limited or no offline download.
  2. Annual subscription: offline areas, extra layers, route sync, sometimes weather or 3D.
  3. One-off region packs: pay once for an area or a bundle, keep it.
  4. Open-source apps: no cost, thinner detail.

Compare the yearly figure with what the same ground would cost in paper maps — a couple of Explorer sheets. If you walk in one national park, a one-off pack may beat a subscription you forget to cancel. Check renewal terms and whether offline areas survive if you stop paying.

Coverage differs across the four nations

England and Wales have recorded public rights of way and access land, and OS Explorer shows them. Legally, the definitive record is held by the local highway authority, not the app.

Scotland works differently. Access rights over most land are statutory rather than tied to a mapped path network, so many routes shown are informal. Terrain detail still matters, but a missing green dashed line means much less north of the border.

Northern Ireland uses OSNI mapping, not Ordnance Survey of Great Britain. Some apps cover Great Britain only. If the Mournes are on your list, check before you subscribe.

Back up the screen with paper

Carry the relevant paper map and a compass, and be able to use them. The app is for confirmation, grid references and quick checks when the cloud comes down. Before you leave, download the area, test it in airplane mode, tell someone your route and return time, and pack a charged power bank. In a UK emergency, call 999 or 112 and ask for Mountain Rescue; a grid reference or a what3words address speeds things up, and an app such as OS Locate will give you a grid reference without any signal at all.

Photo: Kamaji Ogino / Pexels