Mont Blanc Marathon or UTMB: which race to choose?
Written by Victor Michel — history enthusiast and passionate alpinist based in Chamonix. Published August 7, 2026
The Mont Blanc Marathon and the UTMB are two separate events, run by two different organizations, at two different times of year: the Marathon (Chamonix Sports Club, late June, formats from 800 m to 90 km) requires no technical prerequisite, while the UTMB (UTMB World Series, late August, up to 300 km) requires a UTMB Index and a Running Stone. These aren't two tiers of the same race, but two races that share the same massif.
Key takeaways
- Different organizers: Chamonix Sports Club (Marathon, founded 1905) vs UTMB World Series (UTMB, founded 2003)
- Different calendar: Marathon in late June, UTMB in late August
- No UTMB Index required for the Mont Blanc Marathon, unlike every UTMB race
- The Marathon's 90 km is itself a UTMB Index qualifying race (100K category)
Two races, not a hierarchy
The Mont Blanc Marathon and the UTMB aren't two versions of the same event ranked by difficulty: they are two distinct races, with two organizers, two calendars and two registration systems. The Marathon (23, 42, 90 km) is concentrated in the Chamonix valley; the UTMB (up to 174 km for the flagship race, 300 km for the PTL) loops the entire massif across France, Italy and Switzerland. A runner can legitimately target one without ever targeting the other.
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UTMB Index required to register for the Mont Blanc Marathon, versus a mandatory index for every UTMB race
Marathon du Mont-Blanc / UTMB World Series
€479 vs €140
2026 pricing for each event's flagship race: the UTMB (174 km) versus the Mont Blanc Marathon's 90 km
UTMB World Series / Marathon du Mont-Blanc
24 years
gap between the Marathon's creation (1979) and the UTMB's (2003)
Chamonix Sports Club / UTMB World Series
The real common ground: Chamonix, not the organizer
Both races were born in the same Chamonix crucible: the Marathon (then the Cross du Mont-Blanc) in 1979, the UTMB in 2003 — the very year the Marathon took its current name, and the year Michel Poletti, future co-founder of the UTMB, took the start of its very first edition. That link remains historical and local; it translates into no shared organization, pricing or qualification system today.
The Marathon's 90 km, a real bridge to the UTMB
Unlike the rest of the Marathon's program, the 90 km isn't just a standalone race: it's listed by the UTMB as a qualifying race in the 100K UTMB Index category. Finishing it updates the runner's UTMB Index and counts toward eligibility for UTMB World Series races — one of the few concrete crossover points between the two worlds.
| Criterion | Mont Blanc Marathon | UTMB |
|---|---|---|
| Organizer | Chamonix Sports Club (founded 1905) | UTMB World Series (Michel and Catherine Poletti, 2003) |
| Period | Late June (June 24-27, 2027) | Late August |
| Formats | 8 races, from 800 m (Mini-Cross) to 90 km | 8 races, from 15 km (ETC) to 300 km (PTL, teams) |
| Flagship race | 90 km, ≈ 6,200 m D+, 24h cutoff | UTMB, 174 km, 9,900 m D+, full loop of the massif |
| Area covered | Chamonix valley | France, Italy, Switzerland (loop of the massif) |
| Entry requirement | No index required | Valid UTMB Index + 1 Running Stone (last 24 months) |
| Registration system | Lottery (90/42/23 km), priority for residents and low-carbon travel | Lottery after qualification, +30% odds for low-carbon travel |
| Flagship race pricing (2026) | €140 (90 km) | €479 (UTMB, 174 km) |
Read next
- → Mont Blanc Marathon: dates, route, pricing — the complete guide
- → UTMB Mont-Blanc: how to take part
- → Which UTMB race to choose: UTMB, CCC, TDS, OCC or MCC?
- → History of the Mont Blanc Marathon: from the Cross du Mont-Blanc to today
- → Mont Blanc Marathon route: profiles and difficulty by distance
- → Trail training for the Mont Blanc Marathon: 42 and 90 km plan
FAQ
Is the Mont Blanc Marathon easier than the UTMB?
The Marathon's 90 km (≈ 6,200 m D+) is shorter than the UTMB (174 km, 9,900 m D+), but remains a demanding ultra-trail event with a 24-hour cutoff. The 23 km and 10 km, by contrast, are far more accessible and require no prior ultra experience.
Do you need a UTMB Index to run the Mont Blanc Marathon?
No. None of the Mont Blanc Marathon's 8 races requires a UTMB Index at registration — unlike every UTMB race, which all require one.
Does the Mont Blanc Marathon count toward the UTMB Index?
The Marathon's 90 km is listed by the UTMB as a qualifying race in the 100K UTMB Index category. Finishing it updates the runner's index and counts toward eligibility for UTMB World Series races. The Marathon's other formats (42, 23, 10 km) aren't Running Stone races.
Can you run the Mont Blanc Marathon and the UTMB in the same year?
Yes, the calendar allows it: the Marathon takes place in late June, the UTMB in late August, about two months apart. It's even a common strategy to use the Marathon's 90 km as a qualifying race ahead of a UTMB registration.
Which race should you pick to discover trail running in the Mont Blanc massif?
The Marathon's 10 km or 23 km, which require no index or prior experience. The OCC (57 km) remains the most common entry format on the UTMB side, but already requires a UTMB Index in at least the 20K category.
Why does the UTMB cost more than the Mont Blanc Marathon?
The two price tags reflect different formats: the UTMB (174 km, 9,900 m D+, a loop of the massif across 3 countries, 2 to 3 days of racing) requires much heavier logistics than the Marathon's 90 km (88 km, ≈ 6,200 m D+, concentrated in the Chamonix valley).