UTMB is the most prestigious mountain ultra in the world. 171 kilometers (106 miles) around Mont Blanc, starting and finishing in Chamonix, France, passing through Italy and Switzerland, with 10,000 meters (32,800 feet) of cumulative elevation gain. Held the last week of August, with a 46.5-hour cutoff.

The course

A clockwise loop around the Mont Blanc massif. Start in Chamonix at 6:00 PM, 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.

By the numbers

  • Distance: 171 km / 106 miles
  • Vert gain: 10,000 m / 32,800 ft
  • Vert per mile: 309 ft/mi (mountain)
  • High point: Grand Col Ferret, 2,537 m
  • Cutoff: 46h 30m
  • Aid stations: ~10 major + smaller water-only points
  • Date: Last week of August (Friday evening start)

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 (101 km, 6,100 m vert) and OCC (56 km) are easier qualification 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.