Mountain race · France
24–27 June 2027 · Chamonix, Haute-Savoie
90K: Expected Fri, 25 June 2027
One of the most beautiful trail running festivals in the world, with 10,000 runners across 8 races over 4 days beneath Mont Blanc. The flagship 42 km with 2,540 m of climbing is joined by the epic 90 km ultra, the historic 23 km Cross, and a festive 10 km.
2027 dates confirmed
The event window was checked against the organizer website. Individual distance dates and start times remain planning estimates until the detailed schedule is published.
The mapped GPX is carried forward from 2026 until the new course is verified. Use it for course research, then re-check before race day.
Date sourceEntry · 90K · 2027 edition
The entry facts on file are for the 2026 edition (by draw (lottery)), checked 27 Sep 2026. Dates, method and places for 2027 can differ.
From the organizer's page, checked 27 Sep 2026. TrailSplits does not know whether you have a place; the organizer is the final word.
Marathon du Mont-Blanc is a mountain race scheduled for 24–27 June 2027 in Chamonix, Haute-Savoie, France. TrailSplits currently includes 4 mapped courses for this event, with course maps, elevation profiles, weather context, and pacing tools for the uploaded GPX data.
How to get a place: For the 90 km, 42 km, 23 km and Duo Étoilé, half the bibs go by a free draw (2026 edition: entries 23-30 October 2025, results 5 November 2025); 40% are first come for runners travelling by train or bus and 10% for valley residents. The 10 km and shorter races are first come. 2027 information is 'coming very soon'. Organizer's page, checked Sunday 27 September 2026.
TrailSplits is a free, independent route & pacing companion — not the official race. Visit the official Marathon du Mont-Blanc site →
The organizer lists 90K at 88 km and +6,200 m for 2026; the course file mapped here (the organizer's 2026 file) measures 90.3 km. Small differences come from how each figure was measured; plans and pacing here use the mapped file. Organizer's race list, checked Wednesday 30 September 2026.
Racing more than once next year? Add 90K to a season and see whether your races work together.
Inspect the official course track on a topographic map, through its elevation profile, or in 3D.
› running direction two lines: out and back on the same path kilometres
Selected distance
Vert-focused blueprint with route-finder links into the Planner.
Prepare and return
Keep this course, its training plan, calendar and future course updates together in your private My Races page. Saving does not publish your workouts, pace or progress.
Race route lab
Open the official course in Planner, then choose a nearby start point to build a shorter loop that matches the course demand. This course averages about 75 m climb per km.
Expected Fri, 25 June 2027
Send to your watch
Get the official course as a clean GPX or a Garmin TCX course, with step-by-step instructions to load it onto a Garmin, COROS, Suunto, Wahoo, or Komoot — free, no account needed.
Compare your training
See how faithfully your rehearsal route matches the real race. The official course for 90K loads as Route A — upload your training route to compare distance, elevation gain, estimated time, and how much of the course you actually cover.
Course analysis
See the 90K course broken into its major climbs and descents in order — length, gain, average grade, and steepness — so you know where the crux is and how to pace and fuel it.
Race-week reminders
A free browser notification in the final week — the course crux, the weather window, and loading the GPX onto your watch. No app, no email, no account.
Marathon du Mont-Blanc 2027 races run 24–27 June 2027 in Chamonix, Haute-Savoie; the 90K is expected on Fri, 25 June 2027. Check the official race site for registration deadlines and final details.
4 distances (10–90.3 km). The longest course is 90.3 km with about 6,770 m of vertical gain — a demanding mountain course.
The 90K course has a 26-hour cut-off, an average of 17.3 min/km to finish in time. TrailSplits' cut-off pacer shows the buffer at each aid station.
Yes. TrailSplits gives you the course map, an interactive elevation profile, a 3D flyover and a downloadable GPX for every mapped distance — free and with no sign-up.
Each distance has a free, course-specific 16-week training plan built around its distance, vertical gain and cut-offs, plus a pace and cut-off calculator.
No. TrailSplits is a free, independent route and pacing companion. For registration and official rules, visit https://www.marathonmontblanc.fr.
Load the GPX directly into TrailSplits for surface analysis and terrain intel.
Install TrailSplits — a free app you add straight from your browser — and download the 90K course to your phone. Explore the route and elevation offline before race day, then follow it with no signal on the day. No app store, no account, no subscription.