Marathon du Mont-Blanc

The Marathon itself starts early in the morning at the Place du Triangle de l’Amitié. Limited to 2,300 competitors, the runners line up to take on the challenge of running from Chamonix to Vallorcine and back to Place du Triangle de l'Amitié where it all began many hours before.

From the centre of Chamonix (altitude 1,035m) the runners set off along the river Arve, passing through the hamlets of Les Bois and Lavancher. It is a steady climb for about 15km until they reach Argentière at 1,250m. The route then continues towards Le Tour village and then up towards the Aiguillette des Posettes (2,185m) and then through the Chaleyre.

Descending to Vallorcine (1,260m), a quiet village nestled at the bottom of the valley, just on the edge of the Swiss border, then runners move onto Le Buet and head into the heart of the Aiguilles Rouges nature reserve taking the Chemin des Diligences to the Col des Montets (1,461m).

The route ascends until La Flégère (1,875m) after crossing the magnificent Charlanon Coomb (1,812m). A gentle yet progressively steeper descent makes up the final stretch down through the forests, bringing the runners down to town level and a finishing run through the streets to the finish line.

The beginning of the race, from Chamonix to Lavancher is mostly in the shade, however, much of the race is under the full glare of the summer sun. This race is much more gruelling than your average marathon; not only is it over cross-country trails and up steep ascents but Chamonix itself is almost as high as Mount Snowdon – so before the runners even set off they are struggling with racing at high altitude. This is evident in the race times; the average Marathon du Mont Blanc winner usually completes the course in around 4h to 4h30. If you compare this with the more well-known London and New York marathons, where the average winning time is usually just over two hours, you can see a clear difference.

Place du Triangle de l'Amitié and throughout the mountains.

For those who would rather cheer from the sidelines there is plenty to keep you occupied whilst the runners are slogging it out. Giant screens are erected with live feeds to different points of the race, so you can keep an eye on the action from Chamonix. Many people hike up to Flégère (you can take advantage of the lift system if you prefer) to cheer on the competitors as they reach the final stages of their races. The villages along the route often have a good turn-out of spectators, so the runners enjoy plenty of support and there is a good atmosphere throughout the valley. Entertainments such as climbing walls, bungee trampolines and live music add to the fun and the weekend culminates in the prize giving ceremony at Place du Triangle de l’Amitié (the space in front of the tourist office).

There is usually a celebratory buffet meal or ‘Pasta Party’ after the Cross and the Marathon races, giving competitors the chance to meet, chat and congratulate each other on their achievement.

Every year hundreds of volunteers are involved in the organisation of this event. If you would like to volunteer and support the event, visit the website or use the enquiry form the find out more.

This legendary event was first run in 1979 as a 23km cross-country race, with no fewer than 450 entrants. In 2003, on the 25th anniversary of the race, it added a 42km race and became the Marathon du Mont-Blanc. The 23km race remains a part of the event to this day, and over the years other races have been added to the calendar and entrant numbers have increased, meaning organisers have needed to limit entry numbers for some races.

In 2013, the marathon became an official race on the ISF (International Skyrunning Foundation) calendar of international events - Skyrunner Trail Series.

Salomon became the first partner of the marathon in 2003 and remained a name synonymous with the event unp until recently. In 2025, it was announced that New Balance has become its title partner, signing up for the next five years.

If the marathon itself is not something you would see yourself entering, there are a number of other races that take place under the 'Marathon du Mont Blanc' umbrella.

The Spanish ultrarunner Kilian Jornet has dominated the 42km race since 2012, winning a total of five times up until 2018 and is considered the race's most iconic champion. 

Since then, the field has become more international with winners from across Europe, Africa and beyond. Now considered one of the world's top trail marathons, every year sees faster times breaking course records. 

Registration for the marathon events typically opens in October/November of the preceding year. Registration is via a ballot system and is exclusively online.

If you don't fancy running in any of the races, but would like to take part in some way, you can volunteer with the race organisers to help in various roles around the event.

There is prize money for the first three finishers in the men's and women's races for the 42km and 90km, plus the Vertical K fastest time in the both men's and women's category.