90km: an epic race
90km du Mont-Blanc
With a distance of 92 km and a vertical drop of 6330m, the 90km du Mont-Blanc is recognized as one of the most technical trails on the French landscape, and although the course is run exclusively on hiking trails, these are sometimes narrow and airy.
Some sections of the course are run exclusively in the snow, and runners frequently operate at altitudes of between 2,000m and 2,500m, requiring a certain degree of acclimatization. The weather can change rapidly in the mountains (wind, precipitation, heat/cold) and running at night can sometimes increase the feeling of difficulty of a passage.
To take part in this race, it is recommended that you have good mountain running experience, are comfortable on all types of terrain, and are self-sufficient for several hours. We draw your attention to the fact that a runner with an UTMB index of less than 450 points has very little chance of finishing the race, so we recommend that you take part in another Mont Blanc Marathon event.
2025 race route
92km semi-autonomous ultra trail
6330m +/-
Open to Espoir category and above
Limited to 1,000 runners
2 starting waves
Maximum time: 25 hours
8 full feed stations
1 finish refreshment station
Number withdrawal
Number collection for the 90km race will be by appointment only, at the EMC2 space on Place du Mont-Blanc (Chamonix):
Thursday, June 26, 2025 from 9am to 9pm.
Runners must present photo identification and their race bag, including all mandatory equipment, to enable a timing chip to be fitted and equipment to be checked.
No bibs will be issued to runners without their compulsory equipment and identity papers. No race numbers will be distributed on the Friday morning before the start of the race.
Compulsory equipment
- Cell phone: in working order and with a subscription suitable for the country(ies) crossed by the race (France and Switzerland).
- Photo ID card.
- Water supply of at least one liter.
- Waterproof jacket with hood (gore-tex type) adapted to your size.
- Warm second-layer garment (with long sleeves) adapted to your size.
- Headlamp or chest lamp with spare batteries.
- Survival blanket (140cm x 200cm).
- Whistle.
- Tumbler.
- Bowl and spoon.
- Cash.
Recommended equipment
- Cap.
- Tights.
- Gloves.
- Roll of straps.
Time barriers
The time limits given below are for guidance only. In the event of adverse weather conditions, and for safety reasons, the organization reserves the right to stop the event in progress or modify the time limits. All decisions will be taken by the race jury.
A runner arriving at a time barrier after the deadline will be disqualified. The lower right-hand corner of the race number will be "cut out" by the station chief and the runner will be invited to return to Chamonix. Should the runner wish to continue on the course, his or her number will be collected by the station chief and the runner will no longer be considered a participant in the Mont Blanc 90km, and will therefore no longer be under the responsibility of the organizer. Anyone disrespecting the volunteers responsible for enforcing the time limits will be banned permanently from all Mont Blanc Marathon events.
- La Flègère (km 18) : Start time of last wave + 4h30 of race.
- Le Buet feed station (km 27): Start time for last wave + 6h30 of race.
- La Villaz (km 38): Start time for last wave + 9 hrs race.
- Ravitailissement d'Emosson (km 43): Start time for last wave + 11:00 race.
- Le Chatelard (km 47) : Start time for last wave + 12:00 race.
- Ravitaillement du Tour (km 62): Start time for last wave + 16:15 race.
- Ravitaillement des Bois (km 72): Start time for last wave + 18:30 race.
- Montenvers feed station (km 78): Start time for last wave + 9:00 pm race.
- Plan de l'Aiguille refreshment station (km 83): Start time for last wave + 23:00 race.
- Maximum race time - Chamonix finish (92km): Start time for each wave + 25:00 race.
Maximum race time
Runners crossing the finish line after the maximum race time will not be classified and therefore not considered as finishers. This maximum time is calculated according to the start time of your wave.
90km du Mont-Blanc: maximum race time 25h00