Short answer: the UTMB (Ultra-Trail du Mont-Blanc) is 174 km (about 108 miles) with 9,700 m (about 31,800 ft) of climb, a loop around Mont Blanc that starts and finishes in Chamonix, France and crosses Italy and Switzerland. The time limit is 45 hours 30 minutes, and the race starts on a Friday evening in late summer.
UTMB is one race in a week of events on the same trails. The shorter ones are common first steps, and all need Running Stones from UTMB World Series races to enter.
| UTMB | 174 km, 9,700 m+, 45h30 limit, Chamonix to Chamonix |
|---|---|
| TDS | 145 km, 9,500 m+, 44h55 limit, starts Courmayeur |
| CCC | 108 km, 6,200 m+, 28 h limit, Courmayeur to Chamonix |
| OCC | 60 km, 3,500 m+, 14h30 limit, Orsières to Chamonix |
| Entry | Lottery weighted by Running Stones earned at UTMB World Series races |
UTMB is the most prestigious mountain ultra in the world. 174 kilometers (about 108 miles) around Mont Blanc, starting and finishing in Chamonix, France, passing through Italy and Switzerland, with 9,700 meters (about 31,800 feet) of cumulative elevation gain and a 45 hour 30 minute time limit.
The course
A clockwise loop around the Mont Blanc massif. Start in Chamonix on Friday evening, climb out toward Saint-Gervais and Les Contamines as the sun sets. Cross into Italy at the Col du Petit-Saint-Bernard. Through Courmayeur (the iconic mid-point at km 80, base of Mont Blanc on the Italian side). Up over the Grand Col Ferret (2,537m / 8,323ft), into Switzerland through La Fouly and Champex-Lac. Climb back into France over the Col des Montets, descend into Chamonix for the finish.
Most runners are out for one full night and most of a second day. Some take two full nights. The climbs are long (1,000–1,500 meters of vert over 6–10 km is typical) and runnable on the descents but technical at the high passes.
How to qualify (the Running Stones era)
Since 2023, UTMB uses the Running Stones system. Earn Stones by finishing UTMB World Series races (each event awards 1–4 stones based on distance category). Stones convert into UTMB lottery tickets, the more you have, the better your odds. UTMB-distance entry typically requires 4+ stones to be competitive, plus a base of ITRA points.
The qualifying race calendar runs across continents. Realistically, plan 1–2 years of qualifier finishes plus 1–2 lottery cycles to enter UTMB itself. The CCC (108 km, 6,200 m) and OCC (60 km, 3,500 m) are easier targets in the same week.
Gear strategy
- Mandatory kit: UTMB enforces a strict mandatory kit list: waterproof shell, baselayer, gloves, hat, headlamp + spare, food, water, blister kit, whistle, foil blanket. Random checks during the race. Don't skip.
- Vest: 12L+ for the mandatory layers. Salomon Adv Skin 12 or UltrAspire Zygos 5.0.
- Poles: Effectively required. LEKI Cross Trail FX or Black Diamond Distance Carbon Z. Front-carry routing.
- Shoes: Hoka Speedgoat 6, Salomon S/Lab Genesis, or Tecnica Magma. Aggressive lugs for wet rock and grass at the high passes.
- Layers: a real waterproof shell (Patagonia Storm10 or Salomon Bonatti Pro), insulated mid-layer, full glove pair. The high cols can drop below freezing even in August.
- Two headlamps: one primary (Petzl Nao RL), one backup (Petzl ACTIK Core). Mandatory.
Pacing
UTMB does not allow pacers (only family/crew at allowed aid stations). Self-supported except at major aid (Les Contamines, Courmayeur, La Fouly, Champex, Vallorcine, Chamonix). Crew points are limited; some require shuttle access.
Pacing strategy: run conservatively for the first 80km. The race actually starts at Courmayeur. Many runners hit Courmayeur feeling like heroes and DNF in Switzerland 12 hours later. Save the legs for the back half, every climb after Courmayeur is steeper and longer than the climbs before.
Crew strategy
UTMB crewing requires logistics. Many crew teams hire a Chamonix-based shuttle service rather than driving themselves, the mountain passes between aid stations are slow and parking is brutal during race week. Plan to see your runner at Les Contamines, Courmayeur, La Fouly, Champex, and the finish. Don't try to make every aid station; you'll burn out and miss the important ones.
The UTMB experience
UTMB is unlike any other ultra. The crowds in Chamonix are enormous. Spectators on every climb. Cowbells and "allez allez" at 3:00 AM at remote refuges. The course is iconic, it's the original Tour du Mont Blanc trekking route, only run in one weekend instead of seven days. The finish in Chamonix is, for many, the most emotional finish line they'll ever cross. Most who finish describe it as the high point of their endurance career.
Common questions
How long is UTMB?
UTMB is 174 km (about 108 miles) with 9,700 m (about 31,800 ft) of elevation gain, per the official UTMB site. The organizer notes distance and gain can be adjusted for terrain.
What are the UTMB distances?
The main Mont-Blanc week races are UTMB (174 km), TDS (145 km), CCC (108 km) and OCC (60 km), plus shorter races such as MCC and ETC and the non-competitive PTL.
What is the UTMB cutoff time?
The UTMB time limit is 45 hours 30 minutes. The CCC limit is 28 hours and the OCC limit is 14 hours 30 minutes.
How do you qualify for UTMB?
You earn Running Stones by finishing UTMB World Series races; the Stones become lottery chances for the Mont-Blanc finals. Most runners need one to two years of qualifier finishes before they are drawn.
Sources: official UTMB Mont-Blanc race pages (montblanc.utmb.world) for distances, elevation and time limits. Figures change between editions; check the official site before you plan. Researched, not professional coaching advice.
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