How does TrailSim decide which eSIM to recommend?

For each route TrailSim samples the OpenStreetMap geometry every 500 metres and classifies every sample per carrier from public signal data — OpenCellID tower positions, FCC National Broadband Map filings, Ofcom drive tests or the ACMA licence register, chosen per route. The eSIM plans on sale are grouped by the networks they roam on, and the featured plan is the one whose network combination has fast 4G/5G data on the largest share of the route at a sensible price for the typical trip length.

What is in the offline dead-zone map?

A PDF report and a GPX track: every stage of the route with its coverage share and best network, and every continuous dead zone of 2 km or more with its length and GPS coordinates. Load the GPX into Gaia GPS, Komoot, Organic Maps or a handheld GPS and the dead zones appear on your map offline. It is included free with every order on analysed routes.

Are the coverage figures guaranteed?

No. They are estimates from public data: real signal varies with terrain, weather, network load and the phone. Mountain routes modelled from tower positions without terrain are stated as upper bounds, and stretches a survey never visited are marked not surveyed rather than no signal.

How TrailSim works

Where our coverage data comes from, how we pick your eSIM, and what's in the offline map.

1. Where the data comes from

Every TrailSim report starts with the route itself from OpenStreetMap — the actual trail or road, kilometer by kilometer, not a country outline. The signal data on top of it comes from the best public source available for that route's region. We do not claim to have field-tested every kilometer ourselves: each report names its data source and says plainly what kind of evidence it is.

OpenStreetMap route geometry

The actual trail or road, kilometer by kilometer — not a country outline. © OpenStreetMap contributors (ODbL).

OpenCellID tower data

Crowd-reported cell-tower locations and radio technologies (CC-BY-SA 4.0), used for most of the world. A point on your route counts as covered when it sits within a conservative range of a carrier's tower — 5G 3 km, 4G 6 km, 3G 5 km, 2G 12 km.

FCC National Broadband Map — US routes

Each U.S. carrier's own propagation filing of where it claims 4G LTE service, per ~0.1 km² hexagon (public domain). A filing, not a field measurement — the report says so.

Ofcom drive tests — some UK routes

Actual signal strength recorded by Ofcom's survey vehicles driving the road network (Ofcom open data) — used where the vans covered the route, such as the Lake District loop and the North Coast 500; other UK routes use OpenCellID tower data. Stretches the vans never drove are shown honestly as “not surveyed”, never as “no signal”.

ACMA licence register — Australian routes

Australia's daily public register of every site a carrier is licensed to transmit from, by band and power — a licence to transmit, not a measurement, and the report says so. With 2G and 3G switched off nationwide, a licensed carrier site means 4G or 5G. Based on Australian Communications and Media Authority information.

2. How we compare carriers on your route

A country-level coverage percentage means nothing on a trail. We sample your route every 500 meters and model, for each carrier separately, whether that point has fast 4G/5G, only weak or legacy signal, or no signal at all. Every plan on a route page shows its own share of the route with fast data. Our Pick is the plan that carries at least 500 MB a day for the typical trip at the best price among the combinations that hold well on the route; Most 4G/5G (when shown) is the combination with the highest fast-data share regardless of price, with the extra cost stated on the card. The report lists every dead zone by name.

3. The offline dead-zone map

Every order on an analysed route (61 of the 84 in the catalog — the directory marks them "Report included") includes your route as a GPX file and a printable PDF, with each segment colored by expected signal. Load it into Gaia GPS, Komoot or Organic Maps — it works with no connection at all, which is rather the point.

4G / 5G data 2G / 3G only No signal

Before you set off, you know exactly where to download offline maps, where to send the "I'll be unreachable until Thursday" message, and where signal comes back.

4. Installing your eSIM

Check compatibility

Most phones since 2019 support eSIM (iPhone XS+, Pixel 3+, recent Galaxy). Your phone must be carrier-unlocked.

Scan the QR code

We email your eSIM QR code. Scan it in your phone settings over Wi-Fi before you travel — it takes about two minutes.

Turn it on when you land

Enable the eSIM line and data roaming on arrival. No kiosks, no paperwork, no swapping tiny plastic trays at the airport.

Keep your home number

Your physical SIM stays in place for calls and texts; the eSIM handles data on the trail.

Ready to see your route?

Every route page shows its coverage map and the eSIM plans that fit it.

Find my route