Mont Blanc Marathon: dates, route, pricing and mandatory gear
Written by Victor Michel — history enthusiast and passionate alpinist based in Chamonix. Published July 16, 2026 · Updated August 5, 2026
The Mont Blanc Marathon, held every year in late June in Chamonix by the Chamonix Sports Club (CSC, founded in 1905), brings together around 10,000 runners across 8 trail races, from the children's Mini-Cross to the 90 km. The next edition takes place from June 24 to 27, 2027.
Key takeaways
- Next edition: June 24-27, 2027 in Chamonix
- 8 races: 90 km, 42 km, 23 km, 10 km, Vertical KM, Duo Étoilé, Young Race, Mini-Cross
- 2026 reference pricing: from free (Mini-Cross) to €140 (90 km)
- Lottery entry for the 90, 42 and 23 km; direct registration for the 10 km, Vertical KM and Young Race
What is the Mont Blanc Marathon?
Organized by the Chamonix Sports Club, a nonprofit founded in 1905, the Mont Blanc Marathon is one of the largest trail running events in France, with around 10,000 participants each edition. Unlike the UTMB, which loops the entire massif over several days and countries, the Mont Blanc Marathon offers shorter formats (from 800 m to 90 km), concentrated in the Chamonix valley, and runs in late June rather than late August.
≈ 10,000
runners each edition, across all formats
Chamonix Sports Club
1905
year the Chamonix Sports Club, the event's organiser, was founded
Chamonix Sports Club
24 h
maximum cutoff time to complete the 90 km
Marathon du Mont-Blanc
Next edition: dates and program
The next edition takes place from June 24 to 27, 2027. For reference, the 2026 edition followed this 4-day structure: Thursday, bib collection; Friday, 90 km start at 4:45 am and Vertical KM start at 4:00 pm; Saturday, starts for the 23 km (7:00 am), 10 km (10:30 am), Mini-Cross (from 8:30 am), Young Race (7:00 pm) and Duo Étoilé (7:30 pm); Sunday, 42 km start at 7:15 am (elite women at 6:45 am). The detailed hourly program for the 2027 edition is not yet published at the time of writing — check the official site marathonmontblanc.fr ahead of race day.
Pricing and registration: the smart move
Registration for the 90, 42 and 23 km goes through a lottery. The 10 km, Vertical KM, Young Race and Mini-Cross register directly, without a lottery, generally in November — the Mini-Cross stays free regardless of registration date.
Lottery — A random bib-allocation system used when demand exceeds available spots. Registering early doesn't improve your odds: only the priority order affects the outcome.
- Residents committing to public transport — Chamonix valley residents committing to arrive by public transport — highest priority.
- Train or bus commitment — runners committing to arrive by train or bus — intermediate priority.
- General lottery — all other registrants, decided by the general lottery.
Avoid
- Waiting until after 31 March to register for the 10 km or the Vertical KM
- Counting on a last-minute spot for the 90, 42 or 23 km
- Throwing away your 23 km or Vertical KM bib after finishing
Do instead
- Register before 31 March for the 10 km (€32 instead of €40) or the Vertical KM (€37 instead of €45)
- Tick the public-transport option if you're a resident, to maximise your lottery priority
- Keep your 23 km or Vertical KM bib: it's a free lift ride back down to Chamonix
The 90, 42 and 23 km aren't open registrations with instant confirmation: the lottery may not allocate a bib, even to a runner who registered on day one with no particular priority. A firm goal on one of these three races deserves a plan B — the 10 km and Vertical KM register directly, with no lottery.
Since 1979: the story of a race that became a benchmark
The Mont Blanc Marathon traces back to the 23 km, born on 1 July 1979 under the name 'Cross du Mont-Blanc', on the initiative of Georges Costaz and Christian Roussel, then heading the Club Alpin Français de Chamonix. The 42 km and 10 km joined the programme in 2003, the Vertical KM in 2011, the Duo Étoilé and the Young Race in 2015. An ultra-long-distance format, trialled at 80 km in 2013, was extended to 90 km from 2018 — the progression that has made the Mont Blanc Marathon one of the most complete trail events in the Alps, with a format for every level.
| Race | Distance | D+/D− | 2026 reference fee | Runner limit |
|---|---|---|---|---|
| 90 km du Mont-Blanc | 88 km | ≈ 6,200 m | €140 | 1,000 |
| 42 km du Mont-Blanc | 42 km | 2,540 m | €80 | 2,300 |
| 23 km du Mont-Blanc | 23 km | 1,680 m / 870 m | €50 | 2,000 |
| 10 km du Mont-Blanc | 10 km | — | €32 then €40 | — |
| Vertical KM du Mont-Blanc | ≈ 3.8 km | ≈ 1,000 m | €37 then €45 | — |
| Duo Étoilé | — | — | €85 / team | — |
| Young Race | — | — | €30 | — |
| Mini-Cross | 800 m to 3 km | — | Free | — |
The routes: profiles and checkpoints
Cutoff time — The maximum time allowed, counted from the start of the last wave of runners, to reach a checkpoint or the finish. A runner outside the cutoff at a checkpoint is pulled from the race by the organisation, even if they feel able to continue.
42 km du Mont-Blanc — profile and aid stations
| Checkpoint | Km | Cutoff (from last wave's start) |
|---|---|---|
| Le Tour aid station | 13.5 km | + 2h45 |
| Vallorcine aid station | 23.5 km | + 5h30 |
| La Flégère aid station | 34.2 km | + 8h30 |
| Finish — Chamonix | 42 km | + 10h (maximum cutoff) |
23 km du Mont-Blanc — profile and aid stations
| Checkpoint | Km | Cutoff (from last wave's start) |
|---|---|---|
| Montroc aid station | 11.4 km | + 2h30 |
| La Flégère aid station | 18.4 km | + 4h30 |
| Finish — Planpraz, Chamonix | 23 km | + 6h (maximum cutoff) |
90 km du Mont-Blanc — profile and aid stations
| Checkpoint | Km |
|---|---|
| La Flégère | 18 km |
| Buet | 28 km |
| La Villaz | 35 km |
| Emosson | 40 km |
| Le Châtelard | 44 km |
| Le Tour | 60 km |
| Les Bois | 69 km |
| Montenvers | 75 km |
| Plan de l'Aiguille refuge | 81 km |
| Finish — Chamonix | 88 km (24h maximum cutoff) |
Mandatory gear
Mandatory gear is checked at bib collection: without the complete kit in your bag, no bib is issued. The base list is common to the semi-autonomous races (23, 42 and 90 km), with additions depending on the forecast. For the required waterproof jacket, French brands such as Cimalp offer dedicated trail models — their Storm Pro is rated at 20,000 Schmerber and 80,000 g/m²/24h breathability with a 3-layer Ultrashell® membrane.
Schmerber — A unit measuring a fabric's waterproofing: the height of water, in millimetres, it withstands before the first drops get through. The higher the figure, the more the membrane resists heavy or prolonged rain.
Base list
- Charged, functional mobile phone
- Water reserve: 1 L minimum at the start (raised in case of forecast heat)
- Waterproof jacket with hood, Gore-Tex-type membrane, sealed seams
- Headlamp or chest lamp with spare battery
- Survival blanket: 140 cm × 200 cm minimum
- Whistle
- Personal cup: 15 cl minimum
- Food reserve
Addition for cold weather
- Long-sleeve technical top
- Lightweight gloves
- Warm hat or neck gaiter
Addition for hot weather
- Cap or wide-brimmed hat
- Sunscreen
- Sunglasses
Recommended gear: our tips and tricks
Beyond the regulatory list checked at bib collection, a few habits make the difference on the 23, 42 or 90 km.
- Test the entire mandatory kit (jacket, lamp, survival blanket) on a long run before the event, not just at home.
- On the 90 km, pack a spare pair of gloves and a spare T-shirt in a drop bag (a bag handed to the organisation before the start and retrieved at a checkpoint) if the organisation allows it, especially for the night.
- Favour folding poles over telescopic ones for quick stowage between runnable and technical sections.
- Size up half a shoe size from your usual fit: the foot swells over time, particularly on the 42 and 90 km.
- Always store each mandatory item in the same spot in your pack or vest, so you can find it fast during a check or a sudden weather change.
- → Which waterproof jacket for trail running?
- → Which waterproof over-trousers for trail running?
- → Which pack or vest for trail running?
- → Which shoes for trail and ultra running?
- → Which socks for trail and ultra running?
- → Which gloves for trail and ultra running?
- → Which poles for trail and ultra running?
- → Which T-shirt for trail and ultra running?
- → Which shorts for trail and ultra running?
Sources and resources
Read next
FAQ
When is the Mont Blanc Marathon 2027?
From June 24 to 27, 2027, in Chamonix. The detailed hourly program for each race is published by the organization in the months before the event.
What races does the Mont Blanc Marathon offer?
Eight events: the 90 km, the 42 km, the 23 km, the 10 km, the Vertical KM, the Duo Étoilé (team), the Young Race and the Mini-Cross (children's races from 800 m to 3 km).
What is the route and elevation gain of the 42 km du Mont-Blanc?
42 km for around 2,540 m of combined elevation change (D+/D−), with fast-rolling trails in the first part then the technical slopes of the Aiguillette des Posettes, the course's main difficulty, before finishing in Chamonix.
What is the elevation gain of the 90 km du Mont-Blanc?
About 6,200 m of combined elevation change over 88 km, with 9 intermediate checkpoints (La Flégère, Buet, La Villaz, Emosson, Le Châtelard, Le Tour, Les Bois, Montenvers, Plan de l'Aiguille refuge) before finishing in Chamonix, with a maximum cutoff of 24 hours.
How much does registration for the Mont Blanc Marathon cost?
For reference (2026 pricing): €140 for the 90 km, €80 for the 42 km, €50 for the 23 km, €32 to €40 for the 10 km, €37 to €45 for the Vertical KM, €85 per team for the Duo Étoilé, €30 for the Young Race, and free for the Mini-Cross.
How do you register for the Mont Blanc Marathon?
The 90, 42 and 23 km are allocated by lottery, with priority given to Chamonix valley residents, then to runners committing to arrive by train or bus. The 10 km, Vertical KM, Young Race and Mini-Cross register directly, without a lottery, generally in November.
What mandatory gear is required for the Mont Blanc Marathon?
A base common to the semi-autonomous races: charged phone, 1 L of water minimum, waterproof jacket with hood, headlamp with spare battery, survival blanket (140 × 200 cm minimum), whistle and personal cup. Additions are required depending on the forecast (warm layer and gloves in cold weather; cap, sunscreen and sunglasses in hot weather).
Is the Mont Blanc Marathon accessible to beginners?
The 10 km and the Young Race suit a beginner audience. The 23 km and 42 km are classed as semi-autonomous and require prior mountain running experience. The 90 km, with its 24-hour cutoff and significant elevation change, is aimed at experienced ultra-trail runners.
What is the difference between the Mont Blanc Marathon and the UTMB?
Both are held in Chamonix but by different organizations and at different times of year: the Mont Blanc Marathon (Chamonix Sports Club, late June, formats from 800 m to 90 km) precedes the UTMB (late August, up to 300 km for the PTL, a full loop of the massif across several countries). See our dedicated guide to choose between UTMB, CCC, TDS, OCC or MCC.
Can you use mechanical lifts to descend during the event?
Yes, for the 23 km and the Vertical KM: the bib acts as a free transport pass to descend to Chamonix via the mechanical lifts after finishing at Planpraz.