HOKA UTMB Mont-Blanc
UTMB® – Ultra-Trail du Mont-Blanc
Chamonix, France
Race guide
Updated 19 July 2026
The Ultra-Trail du Mont-Blanc is the benchmark of mountain ultrarunning — a 174 km loop circling the entire Mont-Blanc massif through France, Italy, and Switzerland, accumulating 7,660 m of climbing and reaching a high point of 2,486 m. Starting and finishing in Chamonix, the race crosses three countries, threads through alpine villages, and traverses high mountain cols that have become legendary in the sport. With a Sunday 16:15 cut-off, runners have roughly 46 hours to complete the course, though the tightest windows fall in the middle sections after Grand Col Ferret and on the long overnight push through Switzerland back into France. This is a race that punishes ambition and rewards restraint. The terrain is varied — runnable valley paths, rocky singletrack, exposed ridgelines, and technical descents — but the sheer cumulative load across two nights of running is what breaks most runners. Understanding where to hold back, where to push, and how to manage the slow grind between life bases is the difference between finishing and dropping.
Course & Terrain Overview
From Chamonix the route heads immediately into the valley toward Saint-Gervais (21 km, 858 m), a gentle opening that can lull runners into false comfort. The first meaningful climbing begins on the approach to La Balme (42 km, 1,878 m) and continues through to Les Chapieux (55 km, 1,736 m), the first life base. The Italian section follows — up to Lac Combal (68 km, 2,087 m), over Checrouit and into Courmayeur (81 km, 1,276 m) — with sustained ascents and long, quad-taxing descents into the Aosta Valley. The Swiss leg begins after Courmayeur with the climb to Refuge Bertone (89 km, 1,970 m) and the long grind to Grand Col Ferret (104 km, 2,465 m), the highest point on course. From there the descent drops into La Fouly (117 km) and on to Champex-Lac (127 km), the third life base. The return to France crosses into Trient (143 km), climbs again to Vallorcine (153 km), then tackles the brutal final ascent to La Flégère (166 km, 1,702 m) before the final descent into Chamonix. Total footpath character ranges from wide, compacted dirt tracks in the lower valleys to loose, rocky alpine terrain above 2,000 m.
The Decisive Climbs & Where the Race Is Won or Lost
There are several places where UTMB unravels runners, but three stand out. The first is the approach to Grand Col Ferret at 104 km — arriving here after the first full night with legs already carrying 100 km of alpine terrain, the col demands precise effort management. The cut-off is 22:00 Saturday, which sounds generous until you consider the climbing that precedes it from Courmayeur. The second crux is the Champex-Lac to Trient stretch at night — deep into the race, this rolling Swiss woodland section drains mental reserves as much as physical ones. The third, and arguably most critical, is the final climb to La Flégère at 166 km. With less than 10 km to the finish but nearly 500 m of climbing still to come, this is where patience either pays dividends or debt collectors arrive. Runners who went conservatively through the early French valleys and kept something in reserve through Courmayeur consistently find themselves moving well on this climb when others are reduced to a shuffle. The race is not won in the first 80 km — it is merely not lost there.
Pacing Strategy: The Patient Deposit
The valleys between Chamonix and Courmayeur are a trap for the enthusiastic. They feel manageable, the crowds are electric, and the terrain invites running — but they are setting the terms for everything that follows. The most durable approach treats the first 81 km as a deposit, not a performance. Running easy enough to hold a conversation through Les Contamines (31 km) and into Les Chapieux (55 km) is not a sign of weakness; it is the race plan. The real race begins on the far side of the first night, somewhere between Arnuva and Grand Col Ferret, when the accumulated load starts to differentiate field positions. In the second half, particularly through Switzerland, breaking the remaining distance into manageable segments — checkpoint to checkpoint, climb to climb — prevents the enormity of the finish from becoming psychologically crushing. 'Two more checkpoints and I'm home' is a more useful unit of currency than kilometres at hour 30. Runners who trust this process and resist the urge to chase time in the opening stages regularly outperform their expected finish position in the final 30 km.
Fueling & Aid Station Strategy
UTMB has three life bases — Les Chapieux (55 km), Courmayeur (81 km), and Champex-Lac (127 km) — where drop bags can be accessed and crew is permitted at Courmayeur and Champex-Lac. Crew can also meet runners at Les Contamines (31 km) and Vallorcine (153 km). The life bases are where you fix problems, not where you make time — keep stops efficient and targeted. Between life bases, regular aid stations provide hot food, broth, and staples; the Italian and Swiss sections are particularly well-stocked with local provisions. Caloric intake must be deliberate from the very start: waiting until hunger hits at hour 10 is too late. Liquid sodium management is critical through the warmer first afternoon on the Italian side of the course, particularly on the descent into Courmayeur and the climb back out to Refuge Bertone. Front-loading liquid intake and salting consistently through the heat of Saturday afternoon protects the overnight sections where stomach sensitivity typically increases.
Conditions to Expect
UTMB runs in late August, typically starting on a Friday evening. Conditions on the course are highly variable by section and by year. The valley stages below 1,500 m can be warm — sometimes unseasonably so — on the Saturday afternoon crossing into Italy, with temperatures in Courmayeur regularly exceeding 20°C. Above 2,000 m, temperatures drop sharply, particularly on overnight sections through Switzerland. The Grand Col Ferret crossing on Saturday night can be genuinely cold and exposed; a mid-layer and wind shell are not optional. Rain and cloud are common at altitude regardless of valley weather, and the upper sections can see snow in cold years. The descents from La Flégère into Chamonix become slippery when wet. Mandatory kit requirements are strict and enforced; carry everything listed, not because you expect to need it, but because the mountain decides — not the forecast.
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Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-05) · official source
0 km · 1035 m · —
9.1 km · 1009 m · —
22.9 km · 809 m · Fri 22:00
32.6 km · 1148 m · Sat 00:00
52.3 km · 1546 m · Sat 05:15
69.6 km · 1973 m · Sat 10:00
78.5 km · 1961 m · —
83.4 km · 1194 m · Sat 13:15
88.9 km · 1977 m · —
101.8 km · 1768 m · Sat 18:15
116.3 km · 1602 m · Sat 22:30
130.2 km · 1475 m · Sun 02:30
146.8 km · 1303 m · Sun 08:00
158.9 km · 1260 m · Sun 11:15
162.8 km · 1461 m · —
170.4 km · 1875 m · Sun 14:45
177.3 km · 1035 m · Sun 16:30
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