Marathon du Mont-Blanc, live.

Four days of mountain racing above Chamonix

Each June the Marathon du Mont-Blanc fills the trails of the Chamonix valley with 10,000 runners across eight races.

The Marathon du Mont-Blanc began on 1 July 1979 as the Mont-Blanc Cross, when 450 participants took to the trails of the valley and finished at Planpraz. In 2003 a 42 km marathon was added beside the original cross, the Vertical Kilometre followed in 2011 and a long race in 2013, which later became the 90 km. The event is organised by the Club des Sports de Chamonix, a non profit club founded in 1905. The next edition runs from 24 to 27 June 2027.

The 42 km is the race most people know. In 2026 it carried 2,540 m of climbing, with fast rolling trail early on, the steep and technical climb to the Aiguillette des Posettes, aid at Le Tour, Vallorcine and La Flégère, and a finish facing the Mont Blanc massif. The field is capped and sent off in waves.

The 90km du Mont-Blanc is the long day. The 2026 course measured 88 km with 6,200 m of climbing, past Le Buet, Emosson, Montenvers and the Plan de l'Aiguille refuge, on trails that are at times narrow, exposed and still snowy between roughly 2,000 and 2,500 m. The 23 km climbs 1,680 m to finish at Planpraz, the 10 km is a shorter outing with 325 m of climbing, and the KM Vertical gains 1,000 m in 3.8 km to Planpraz at 2,000 m.

The organiser presents the 10 km as a race open to everyone and a chance to try trail running, while the 42 km and the 90 km ask for real mountain experience and the ability to be self sufficient for several hours. The KM Vertical is an alpine race whose final section is exposed, with via ferrata style steps and cables, and poles are not allowed. Check the organiser's programme for the 2027 schedule, which is set day by day.

On Livebib you can follow a participant who chooses to share their own live position from the phone they carry. This is not the organiser's timing, and the official results come from the Marathon du Mont-Blanc organisation.