2nd July 2021


04:00 am


85 km

Difference in height

6020 m +/-

ITRA Points

4 ITRA points



The Mont-Blanc 90 km race has become legendary in the Chamonix Mont-Blanc Valley. With its 85km and 6020 meters of vertical drop, it has been recognized as one of the most technical trail races in France. Although the route uses only hiking trails, these are sometimes narrow and breathtaking. Despite its difficulty, this race is one of the most beautiful!

Some sections of the route take place exclusively in the snow and runners evolve very frequently between 2000m and 2500m of altitude, which requires a certain acclimation. Weather can change rapidly in mountains (wind, precipitation, hot and cold) and running at night can sometimes increase the sensation of difficulty.

To participate to this race, it’s recommended to have a good mountain race experience, to be comfortable on any ground and to be autonomous for several hours. We draw your attention to the fact that a runner with no ITRA cotation higher than 450 points (check your odds) has very little chance to finish the race. In that case, it’s more recommended to participate in another race of Mont-Blanc Marathon.

Before to register, we strongly recommend that you read the route, profile and estimated passage times to be fully aware of the difficulty of this race. The time barriers indicated take into account possible slowdowns that you may encounter and we strongly advise you to plan your race with a margin over time barriers.

Date : 2nd July 2021
Start : 04:00 am
Place of start : Paragliders landing field in Chamonix
Distance :
85 km
Distance of heights : +/- 6020m
ITRA pointss : 4 (references : ITRA)

ULTRA TRAIL in semi-autonomy
Start to ‘Espoir’ Category
Limite to 1000 runners.
Maximum time : 24:00 
8 refreshment points

Bib collection on Thursday 1st July at Place du Mont-Blanc by appointment.

To collect their bib, contestant will have to choose a time slot prior to coming. No bib will be given if the runner come out of their chosen time slot.

During the delivery of the bibs of the Mont-Blanc 90KM, runners will have to present a photo ID and their race bag including all the mandatory equipment for equipment inspection. Thanks to this, the organisation will be allowed to put a chronometric chip on them. No bib will be given to runners who don’t have their bag including all mandatory equipment.

  • Mobile phone. It must work and have a subscription adapted to the countries (France and Switzerland). 
  • A reserve of at least 1 litre of water.
  • Waterproof and windproof jacket with hood (gore tex type) adapted to your size.
  • Clothing hot of second layer with long sleeve adapted to your size.
  • Headlamp or chestlamp with spare batteries.
  • Survival blanket (140cm x 200cm).
  • Whistle.
  • Personal cup, a bowl and a spoon.
  • A photo ID.
  • Mask

The time restrictions indicated below are given as an indication, they may be modified if necessary for the safety of the participants. In case of bad weather, and for security reasons, the organisation keeps the right to stop the event in progress or to change the time barriers. Any decision will be taken by the trail committee.

The arrival of a runner on a time barrier outside the deadline implies his disqualification. The lower right corner of the bib will be “cut” by the person in charge and the runner will be invited to use public transport to return to Chamonix. If the runner wishes to continue the race, his bib number will be given to the person in charge and the runner will no longer be considered as a participant in the Mont-Blanc 90 km, so he will no longer be under the responsibility of the organiser.

Anyone who doesn’t respect the volunteers in charge of this function will be banned from racing permanently on all events of the Mont Blanc Marathon.

  • Flégère (km19) : starting time of the last wave + 4h30.
  • Refreshment of Le Buet (km 28.2) : starting time of the last wave + 6h30.
  • Refreshment of Vallorcine (km 43) : starting time of the last wave + 10h00.
  • Refreshment of Le Tour (km 54) : starting time of the last wave + 13h30.
  • Refreshment of Les Bois (km 67) : starting time of the last wave + 17h30.
  • Refreshment of Montenvers (km 72) : starting time of the last wave + 19h45.
  • Refreshment of the refuge du Plan de l’Aiguille (km 78.7) : starting time of the last wave + 22h15


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 Marathon Clips 

Réalisation : Coax – 2021.