The Mont Blanc Marathon is one of the legendary mountain trail events. Every summer, the Mont Blanc Marathon attracts thousands of runners from all over the world, ready to tackle the demanding trails of the massif. For its 2026 edition, scheduled from 25 to 28 June, the Chamonix event is continuing its transformation: more responsible, more local, more inclusive. With eight months to go to the start, the organisers are announcing opening of registrations and a number of major innovations that mark a turning point in the history of the race.
Organised since 1979 by the Chamonix Sports Club, the Mont Blanc Marathon has never stopped evolving, while remaining true to its founding values: respect for the mountains, a spirit of sharing and setting an example.
In 2026, an unprecedented measure will salute this attachment to the region: 10 % of the race numbers will be reserved for residents of the Vallée de Chamonix - Servoz, Les Houches, Chamonix-Mont-Blanc and Vallorcine.
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These "Chamonix numbers", accessible without a draw, will be allocated according to the principle of first come, first served. The races concerned are the 90km, 42km, 23km and the Duo Étoilé.
To be eligible, participants must live in the Valley, present a valid ViaCham card and commit to coming to the event by train, bus, foot or bike.
"We want to highlight those who live here all year round, and whose participation has virtually no carbon impact. It's also a way of thanking the people of the Valley, who are an integral part of the Marathon's soul. stresses the organising committee.
A model race for eco-responsibility
A pioneer in sustainable mountain running, the Mont Blanc Marathon has confirmed its position as a benchmark event.
Back in 2025, the organisers redesigned the registration system to encourage the use of public transport: 40 % race numbers were reserved for participants travelling by train or bus, with no draw.
Mandatory carbon offsetting for all participants, whatever their mode of transport. Local food supplies, dry toilets, waste sorting and elimination of single-use plastic.
The results were impressive, with 20 % less fossil-fuelled cars used, 48 % of participants travelling by train or bus (compared with 25 % in 2024) and €42,000 raised for carbon offsetting, which was donated to the Association Française d'Agroforesterie.
In 2026, the bar is set even higher: 50 % of the race numbers will now be allocated without a draw to runners who come by public transport.
Registrations: a precise timetable not to be missed
Registrations will open on Monday 20 October 2025, in several phases:
- 20 October at 10.00 am Opening of race numbers for "Chamonix Valley residents" (10 % places).
- 22 October at 10.00 am Train-bus" race numbers open (40 % places).
- From 23 to 30 October Entries subject to a draw for longer distances.
- 5 November Publication of results.
- 6 November Open for other races without a draw (10km, KV, The Young Race, Mini-Cross).
The solidarity and environmental bibs, which support young athletes from the Club des Sports and mountain conservation projects respectively, will be available from 2pm on 5 November.
By 2025, these initiatives had raised €85,000, divided between 13 local sports sections and a number of environmental initiatives in the Valley.