Buyer's guide
The best free offline trail map apps
Which mapping apps actually work with no cell service — and which charge for offline. An honest, no-hype rundown for hikers, hunters, surveyors, and SAR teams who can't afford their maps to fail.
How they compare
| App | Paid plan | Free tier | Offline maps | Custom import | Open source |
|---|---|---|---|---|---|
| mapper.one | Free | Free forever | Free | KML/KMZ/GeoJSON/GPX | Yes |
| Avenza Maps | $49.99/yr (Plus) | 3 maps | Your maps | Geo-PDF/GeoTIFF/KML | No |
| onX | $34.99–$99.99/yr | Trial only | Paid | Limited | No |
| Gaia GPS | ~$39.99/yr | Limited | Premium | Yes | No |
| AllTrails | $35.99/yr (+) | No offline | Paid | Limited | No |
| CalTopo | $20–$100/yr | Desktop only | Paid (mobile) | Yes | No |
Pricing reflects publicly listed rates (checked 2026) and can change; verify with each vendor.
What "offline" really means in the field
"Offline" gets used loosely. The question that matters in the backcountry is whether the basemap tiles render with the radio off, not just whether your saved routes show up. Several popular apps let you view routes offline but put offline basemap downloads behind a paid tier.
mapper.one caches OpenStreetMap tiles to durable on-device storage, so any area you viewed before leaving the trailhead is available with no signal — for free. The honest trade-off is that mapper.one does not bundle proprietary layers (slope-angle shading, landowner parcels, curated trail databases); it leans on OpenStreetMap plus the data you import.
The rundown
1. mapper.one — best for free, offline, bring-your-own-data
Free and open-source, with offline OpenStreetMap caching, on-device KML/KMZ/GeoJSON/GPX import, and field waypoints. No subscription and no account. The trade-off: no proprietary layers (landowner data, slope-angle) and no curated trail database — you bring the data.
Get the app →2. CalTopo — best for desktop planning that you carry offline
Unmatched desktop planning, printing, and SAR coordination. The mobile/offline tiers are paid ($20–$100/yr). Many people plan in CalTopo and carry a free field app like mapper.one.
Full comparison →3. Gaia GPS — best premium layer catalog
Deep premium layers (slope-angle, weather, NatGeo/USGS). Offline downloads require Premium (~$39.99/yr). Worth it if you live in those layers.
Full comparison →4. onX — best for landowner & hunting-unit data
Proprietary parcel/landowner boundaries and hunting layers no free app replicates. Subscription-only ($34.99–$99.99/yr), with a trial rather than a free tier.
Full comparison →5. AllTrails — best for discovering popular trails
Huge curated trail database with reviews and photos. Offline maps require AllTrails+ ($35.99/yr). Great for discovery, less for bring-your-own-data fieldwork.
Full comparison →6. Avenza Maps — best for georeferenced PDF map packs
The standard for geo-PDF/GeoTIFF maps and the Avenza Map Store. Free tier caps at 3 maps; Plus is $49.99/yr. Ideal if your maps arrive as georeferenced PDFs.
Full comparison →Start mapping for free
mapper.one is free, open-source, and offline-first. Bring your own data and head out — no subscription, no account.