UTMB Ultra Trail Du Mont-Blanc

The Ultra-Trail du Mont-Blanc (UTMB) is a 174 km trail race held in late August, and perhaps the most renowned trail race in the world.

The course gains 9,900 m over 174 km (56.9 m/km), starting and finishing in Chamonix and looping through Italy and Switzerland on the emblematic Tour du Mont-Blanc route.

Entry costs €479 (~€2.75/km), allocated by lottery — the race is perennially oversubscribed. The biggest climb rises 1,556 m — the 23rd largest single ascent of 385 European trail distances tracked. Just 13.6% of the course is flat — the 76th least-flat of 390 European trail distances. 16.89 km of uphill terrain exceeds 20% gradient. The top descent drops 1,258 m over 9.6 km with a max gradient of 58.78%.

Weather is notoriously variable: 2025 conditions included rain, wind, and snow at the high passes; historical DNF rates reach 35–42% in bad-weather editions.

Nearest airport is Geneva (GVA), approximately 87 minutes by car. [DTR: Airport to Start Transfer Time] Founded in 2003 by Catherine and Michel Poletti, the UTMB drew 2,500+ starters in 2025 with 1,665 finishers. It suits ambitious, highly qualified trail runners with deep alpine experience who want to run the race that defines the sport.

Q: How do you qualify for and enter the UTMB? A: Entry requires UTMB Running Stones accumulated through UTMB World Series qualifier races, plus a successful lottery draw. For the 2026 edition, pre-registration ran January 8–19; lottery results were announced January 22, with waiting-list outreach in early February. Check montblanc.utmb.world for the 2027 registration timeline. Entry fee is €479 per runner (includes a €1.50 environmental tax and €13 Friends of UTMB membership). The race is perennially oversubscribed — qualifying stones are a hard prerequisite, not a guarantee of entry.

Q: What is the weather like at UTMB — and how dangerous can it get? A: Highly unpredictable. The UTMB runs late August across the Mont Blanc massif; conditions at high passes (2,500m+) can shift from sunshine to freezing rain and snow within hours. In 2025, conditions at high passes included rain, wind, and snow; warming huts were opened at summit sections to protect runners in distress. [Race Report: Matt Urbanski, Team RunRun, 2025] Full mandatory gear — waterproof jacket, thermal layers, emergency blanket — is required throughout. Historical DNF rates of 35–42% in bad-weather editions give context to the stakes.

Q: How do you get to Chamonix from Geneva airport for the UTMB? A: Geneva airport (GVA) is approximately 87 minutes by car from Chamonix. Direct shuttle buses run from GVA to Chamonix — no car required. Lyon (LYS) and Milan Malpensa (MXP) are alternative airports at approximately 2.5–3.5 hours. UTMB race week transforms Chamonix into a global trail running festival; accommodation sells out months or years in advance. Book immediately on receiving lottery confirmation — do not wait.