# Tour du Mont Blanc (TMB)

Source: https://trailsim.com/routes/tour-du-mont-blanc (TrailSim — route-matched travel eSIM with an offline dead-zone coverage report included). Countries: France, Switzerland, Italy. Typical trip: about 8 days.

TrailSim estimate for the Tour du Mont Blanc: up to 35% of its 166 km has fast 4G/5G data, a further 38% has slow 2G/3G only, and 4 dead zones total 44 km (real cell-tower data, snapshot 2026-09-07).

The signal is strongest between La Flégère and Le Crozat, where the model puts fast 4G/5G data at up to 100% of the stage. It runs thinnest between Arnuova Desot and Issert (0% fast data) — expect long stretches where maps and messages crawl or fail.

## Key figures

- Route analysed: 166 km, sampled every 500 m
- Fast 4G/5G data (usable data): up to 35% of the route
- Slow 2G/3G only: 38%
- Dead zones (continuous 2 km or more with no signal on these networks): 4 totalling 44 km
- Networks compared: Networks: Salt · Sunrise · SFR · Iliad · Vodafone · Wind
- Data source: OpenCellID (CC-BY-SA 4.0), snapshot 2026-09-07 — mountain upper-bound estimate from tower positions, no terrain modelling
- Estimate, not a guarantee: real signal varies with terrain, weather and network load.

## Stages (preview)

| Stage | km | 4G/5G | 2G/3G | No signal | Best network |
| --- | --- | --- | --- | --- | --- |
| La Flégère → Le Crozat | 0–25 | 100% | 0% | 0% | SFR |
| Le Crozat → Col de la croix du bonhomme | 25–50 | 42% | 26% | 32% | SFR |
| Col de la croix du bonhomme → Col de la Youlaz | 50–75 | 2% | 52% | 46% | SFR |
| Col de la Youlaz → Arnuova Desot | 75–100 | 80% | 20% | 0% | Vodafone |

All 7 stages are in the PDF report included with the eSIM.

## Dead zones (preview)

| # | Near | Section | Length | Signal drops at | Returns at |
| --- | --- | --- | --- | --- | --- |
| 1 | La Rollaz | 39–47 km | 8 km | 45.79015, 6.71497 | 45.73227, 6.70831 |

…and 3 more dead zones, each with GPS coordinates, in the PDF and GPX report.

## eSIM plans

Fixed plans from $3.00 to $68.00 USD (10 options on the default validity shelf); pay-by-the-day plans from $0.90 per day (300 MB–1.5 GB a day at full speed, then slower, 1–90 days set on the payment page). Prices are live on https://trailsim.com/routes/tour-du-mont-blanc. Days start on first use; 14-day self-service refund before installation; Stripe checkout in USD.

## Frequently asked questions

**Is there phone signal on the Tour du Mont Blanc?**

On the networks TrailSim sells for the Tour du Mont Blanc, up to 35% of the route's 166 km has fast 4G/5G data and a further 38% has slow 2G/3G only; 4 modelled dead zones totalling 44 km have no signal on its networks. This is a mountain estimate from tower positions without terrain modelling — treat it as an upper bound; field reports put reliable data lower at high altitude. Cell service depends on which networks your eSIM roams on: the plans on TrailSim's Tour du Mont Blanc page are compared against exactly this route, and every dead zone is named and pinned with GPS coordinates in the coverage report included with each eSIM.

**How much data do I need for the Tour du Mont Blanc?**

Tour du Mont Blanc (TMB) typically takes about 8 days — around 4 GB at 500 MB a day, and the featured plan is picked on exactly that arithmetic. Worldwide, everyday smartphone use averages about 22 GB a month — roughly 730 MB a day — most of it video streaming (Ericsson Mobility Report, Nov 2025). On the trail the picture is lighter: with maps downloaded and video saved for wifi, messaging, photos, weather and bookings run 200–400 MB a day, so we size every recommendation at 500 MB a day for comfortable headroom. Size up if you stream, video-call or share your connection. If you would rather pay only for the days you are out, TrailSim's pay-by-the-day plans for the Tour du Mont Blanc give a full-speed daily allowance that slows down instead of cutting off, with the number of days set on the payment page.

**What is a pay-by-the-day eSIM plan?**

A daily allowance of 300 MB to 1.5 GB at full speed, then slower for the rest of that day — never cut off. It is priced per day: you set the number of days (1 to 90) on the payment page, pre-filled with the typical Tour du Mont Blanc trip length, and the days start on first use. It suits short trips and people who would rather never run out than carry a large fixed plan; the fixed plans on the same page are cheaper per gigabyte for a long trip.

**When do the plan days start counting?**

On first use — installing the TrailSim eSIM and connecting starts the clock, not the purchase date. You can safely buy weeks before your trip.

**Does my phone support eSIM?**

Most phones released since 2019 support eSIM, including iPhone XS and later, Google Pixel 3 and later, and most recent Samsung Galaxy models. Your phone must also be carrier-unlocked.

**Why not a regular travel eSIM from Airalo or Holafly?**

Any eSIM connects to the same physical networks. What TrailSim adds is the route check: it compares real cell-tower data along the Tour du Mont Blanc itself, picks the network combination that holds best there, and includes the coverage report with every dead zone mapped — so you know before you go where the phone will and won't work. A longer comparison is at trailsim.com/compare/airalo and /compare/holafly.

**What if parts of the route have no signal at all?**

On most wild routes some stretches have no signal from any network — no eSIM can change that. TrailSim's Tour du Mont Blanc coverage report marks every dead zone with GPS coordinates and length, so you can download offline maps for those sections and tell people at home when you'll be unreachable. Knowing where it drops is the point.

**What if I change my mind after buying?**

Uninstalled eSIMs qualify for a full self-service refund within 14 days of purchase — no questions asked. Once the eSIM is installed on a device it can no longer be returned.

## Related routes

- Walker’s Haute Route (Chamonix–Zermatt): https://trailsim.com/routes/walkers-haute-route
- EuroVelo 6 (EV6 / Atlantic–Black Sea Route): https://trailsim.com/routes/eurovelo-6
- EuroVelo 6 — France (Atlantic–Basel): https://trailsim.com/routes/eurovelo-6-france
- Camino de Santiago — Camino Francés (French Way): https://trailsim.com/routes/camino-de-santiago

All 84 routes: https://trailsim.com/routes · Coverage index: https://trailsim.com/coverage-index · Glossary: https://trailsim.com/glossary

Route and place names © OpenStreetMap contributors (ODbL). © 2026 TrailSim.