The course and start time for UTMB, trail running’s blue riband event, have both been changed for the 2025 renewal on August 29th.
UTMB is the centrepiece of a week-long event named after it, the UTMB World Series Finals. Based in Chamonix, France, it sees over 10,000 runners compete in eight different races, with OCC and CCC the next most prestigious.
A brutal 176km route is normally what faces UTMB runners as the iconic event takes in three countries on a journey around Mont Blanc and features 9,915 metres of climbing.
But the weather in the area has been mixed this summer and organisers announced a revised route three weeks before race week, citing landslides.
Rethink required
A statement from UTMB read as follows: “Recent landslides between Chamonix and Les Houches have led teams to rethink this section of the route.
“After several field studies, a variant was chosen to ensure your safety while preserving the spirit of the original route.
“The final route of the UTMB is therefore 174km and 9,900 elevation gain”.
That is still comfortably above the classic 100-mile distance for the sport’s biggest events and changes aren’t unprecedented as there can be modifications due to weather or route condition.
As recently as 2023, organisers took the decision to alter the route, changing the Col des Montets section. Runners instead headed via the Béchar and the Bois de la Trappe, a variation planned for bad weather conditions.
No Dauwalter vs Schide clash
In summary, the 2025 the changes are as follows:
The start time has been moved 15 minutes earlier – it will now take place on Friday, August 29th at 17:45 local time, still from the Place du Triangle de l’Amitié.
The section between Chamonix and Les Houches will follow a new route due to the recent landslides.
In order to limit the race’s impact on the Contamines-Montjoie Nature Reserve, and in agreement with ASTERS (the Haute-Savoie Nature Conservancy), the La Balme aid station (at kilometre 40) will be removed. The aid stations at Les Contamines and Les Chapieux will remain available and will be reinforced to compensate for the removal of La Balme.
There are no changes to the timing cut-offs.
The elite fields are still being finalised but what we do know is that three-time women’s champion Courtney Dauwalter is returning to Chamonix as she looks to regain her title – but defending champion and great rival Katie Schide won’t be there to take her on.
