The Mont-Blanc Marathon 2027 (Marathon du Mont-Blanc) will take place from Thursday 24 to Sunday 27 June 2027 in Chamonix, France. Registration opens in November 2026, in several phases: on the most popular races, part of the bibs is reserved for runners travelling by train or bus, and the rest is allocated by lottery. As the official coach of the Mont-Blanc Marathon, RunMotion Coach explains how it works and how to give yourself the best chance of getting a bib.
Updated 4 November 2026: the organisers have confirmed the 2027 dates and a registration opening in November 2026, but the detailed schedule has not been published yet. The process described below is the one used for the 2026 edition. We will update this article as soon as the official announcement is out.
The short answer
- Dates: Thursday 24 to Sunday 27 June 2027, in Chamonix.
- Registration: during November 2026, in several phases. The detailed schedule is not known yet.
- Lottery: in 2026, it covered 50% of the bibs for the 90 km, 42 km, 23 km and Duo étoilé. Entry was free, with one race only.
- Train or bus: 40% of the bibs for these races were reserved, with no lottery, for runners travelling by public transport.
- No lottery: the 10 km, the Vertical Kilometer, The Young Race and the Mini-Cross are first come, first served.
Contents
When is the Mont-Blanc Marathon 2027?
The 2027 edition will run from 24 to 27 June 2027, over four days in Chamonix. The organiser, the Club des Sports de Chamonix, announced the dates on the official Mont-Blanc Marathon website.
The day-by-day programme has not been released yet. As a guide, in 2026 the 90 km started early on Friday morning, the 23 km on Saturday and the 42 km on Sunday. Wait for the organisers to confirm before booking accommodation around a specific race.
The Mont-Blanc Marathon races
Behind the name “Mont-Blanc Marathon” there is actually a whole week of races, from the Vertical Kilometer to a 90 km ultra. They differ both in difficulty and in how you register.
| Race | Distance | Elevation gain | Places (2026) | Access |
|---|---|---|---|---|
| 90 km du Mont-Blanc | 88 km | 6200 m | 1000 | Lottery or train/bus quota |
| 42 km du Mont-Blanc | 42 km | 2540 m | 2300 | Lottery or train/bus quota |
| 23 km du Mont-Blanc | 23 km | 1680 m | 2000 | Lottery or train/bus quota |
| Duo étoilé | Night race in pairs | – | – | Lottery or train/bus quota |
| 10 km du Mont-Blanc | 10 km | – | 2000 | Direct registration |
| Vertical Kilometer | 3.8 km | 1000 m | 700 | Direct registration |
The organisers do not require a minimum UTMB Index, but they do warn that below 450 points on the 90 km, 350 on the 42 km and 270 on the 23 km, your chances of finishing are very low, and they suggest choosing another race of the event. The index is also used to set the start waves: without one, you start in the last wave.
How to register for the Mont-Blanc Marathon 2027
Registration is online only, on the official website, with card payment. For the 90 km, 42 km, 23 km and Duo étoilé, the 2026 edition split the bibs into three access routes. The principle should stay similar in 2027, but the percentages and dates are still to be confirmed.
Bibs for Chamonix valley residents (10%)
10% of the bibs were reserved for residents of the Chamonix valley (Servoz, Les Houches, Chamonix-Mont-Blanc and Vallorcine), with no lottery. Applicants needed a main residence in the valley, a ViaCham card valid during the event, and had to commit to reaching the start by train, bus, on foot or by bike. In 2026, this phase opened on 20 October 2025 at 10:00 (Paris time).
Train and bus bibs (40%)
This is the main way to get a bib without the lottery: 40% of the bibs were reserved for runners travelling to Chamonix by train or bus, on a first come, first served basis. In 2026, this phase opened on 22 October 2025 at 10:00.
The conditions are strict: more than half of your journey from home to Chamonix must be by train or bus, with a return ticket covering your race dates. The ticket has to be uploaded to your runner account before a deadline in the spring (4 May for the 2026 edition). A missing or fraudulent ticket means your entry is cancelled, with no refund.
The lottery (50%)
Half of the bibs are allocated by lottery. In 2026, entries were open for one week, from Thursday 23 October 2025 at 10:00 to Thursday 30 October at 12:00, and results were sent by email on 5 November. Entering the lottery is free: you only pay for your bib if you are drawn, when you complete your registration.
Note that you can only enter one of the four races in the lottery. Pick the one that truly matches your level rather than the most prestigious one.
Races without a lottery
The 10 km du Mont-Blanc, the Vertical Kilometer, The Young Race and the Mini-Cross do not go through the lottery. In 2026, registration opened on 6 November 2025 at 10:00, until places ran out. Here too, part of the bibs is reserved for runners using public transport: on the 10 km, 800 train and bus bibs and 1200 for other means of transport; on the Vertical Kilometer, 280 and 420.
Solidarity and environment bibs
The organisers also offer solidarity bibs, which fund the youth sections of the Club des Sports de Chamonix, and environment bibs, created in 2024 to fund nature protection in the valley. You get one in exchange for a donation, on top of the entry fee. For the 2026 edition, they went on sale on 5 November 2025 at 14:00.
What to plan for when you register
Whatever your access route, carbon offsetting of your return trip to Chamonix is mandatory, with proof of address. It is added to the entry fee. Use a personal email address you check often: that is where you will receive your confirmations and, if relevant, the lottery results.
Entries are firm and final. Only cancellation insurance, taken out when you register, lets you request a refund, under the insurer’s conditions. The rules of recent editions also banned transferring your bib to another runner.
The organisers have not published the 2027 entry fees yet. As a guide, the fees recorded for the 2026 edition were €140 for the 90 km, €80 for the 42 km, €50 for the 23 km, €85 per team for the Duo étoilé, €32 to €40 for the 10 km and €37 to €45 for the Vertical Kilometer, depending on when you registered.
How to improve your chances of getting a bib
The most effective lever is the train or the bus. Public transport bibs do not depend on luck but on speed: note the opening date, create your runner account in advance and be online at the right time. If you are travelling from abroad, check now that reaching Chamonix by train or coach is realistic for you, tickets included.
If you go through the lottery, choose a race that matches your experience. The 23 km is the most accessible of the three, even if it remains demanding with 1680 m of elevation gain; the 42 km already requires real experience of mountain running, and the 90 km is for trail runners with ultra experience. And if you are not drawn, the 10 km and the Vertical Kilometer remain open without a lottery, as do the solidarity bibs.
To make sure you don’t miss anything, sign up for the Mont-Blanc Marathon newsletter: that is where the organisers announce the schedule and rules for each edition.
Train with the official coach of the Mont-Blanc Marathon
Got your bib? RunMotion Coach builds your personalised plan around your race, your level and your availability, taking elevation into account. Try the app free for 7 days.
How to prepare for the Mont-Blanc Marathon 2027
Between registering in November and the start at the end of June, you have about seven months. That is plenty of time, as long as you use it well: build your endurance over the winter first, then make your training more and more specific in the spring, with plenty of climbing and descending.
The Mont-Blanc Marathon races each have their own demands. The end of the 42 km includes a long descent to Chamonix, the 23 km is mostly uphill, and the 90 km strings together big climbs. So you need to work on hike-and-run training, hills and downhills, without forgetting strength work. We cover all of this, race by race, in our Mont-Blanc Marathon training plan.
Depending on your distance, you can also use our 20 km trail, trail marathon or 100 km ultra-trail training plans. And for inspiration, read the stories of RunMotion runners: Yannick, 90 km finisher, Nico, who completed the 90 km in under 19 hours, and Majida, age-group winner on the 42 km.
FAQ
When does registration for the Mont-Blanc Marathon 2027 open?
The organisers announce an opening during November 2026, in several phases, with no exact date yet. For the 2026 edition, the first phases opened as early as 20 October 2025.
Is the Mont-Blanc Marathon lottery free?
Yes. In 2026, entering the lottery was free. You only pay your entry fee if you are drawn.
Can I enter the lottery for several races?
No, one race per runner among the 90 km, 42 km, 23 km and Duo étoilé.
Do I need a UTMB Index to run the Mont-Blanc Marathon?
It is not mandatory. The organisers do recommend an index of at least 450 for the 90 km, 350 for the 42 km and 270 for the 23 km, and use it to place runners in the start waves.
Can I sell or transfer my bib?
No. The rules ban bib transfers, and entries are non-refundable without cancellation insurance.
Drawn in the lottery or got in through the train quota? Start your 7-day free trial and let the official coach of the Mont-Blanc Marathon build your preparation all the way to Chamonix.
Updated 4 November 2026.
