# Marathon du Mont-Blanc 2026: Chamonix Welcomes the World's Best Trail Runners
Chamonix in late June has a specific kind of light. The sun reaches the valley floor by 8:30am and lingers on the south-facing slopes until past 9pm. The Mont Blanc massif — visible from any point in the town centre, the 4,810-metre summit and the Aiguilles de Chamonix arrayed beneath it like a geological cathedral — catches the morning light first, then holds it longest in the evening. The conditions in the valley shift hour by hour: cool in the shade beneath the Drus, warm in the open sections near Argentière, alpine and exposed above 2,500 metres.
This is the landscape that hosts the Marathon du Mont-Blanc weekend — Europe's most decorated trail-running gathering, returning for its 2026 edition June 25-28, less than a week from now.
The race week has begun. Athletes are arriving. The town is preparing for what is, by any honest measure, the most internationally significant trail-running festival on the European calendar.
What the Marathon du Mont-Blanc Actually Is
The Marathon du Mont-Blanc is not a single race. It is a multi-distance festival across four competition days, distinct from but complementary to the larger UTMB week that returns to Chamonix every August. Where UTMB is the August showcase of multi-day mountain ultras, the Marathon du Mont-Blanc is the late-June trail-running championship that focuses on shorter elite-paced racing on technical alpine terrain.
The 2026 race lineup:
Thursday June 25 — KMV (Vertical Kilometer) The vertical kilometer is the discipline's pure expression: 3.8 kilometres of trail with 1,000 metres of elevation gain, starting from Chamonix town centre (1,035m) and climbing the steep wooded north flank of the Brévent to Plan Praz (2,035m). World-class elite competitors finish in under 35 minutes. The course record stands at 31:09.
Friday June 26 — Cross (10K) and Mini-Cross (5K) Family-friendly distance racing through the valley floor and lower wooded sections.
Saturday June 27 — 90K and 23K The 90K — the festival's signature ultra — is the day's centrepiece. The course traces a horseshoe through the upper Chamonix valley, summitting at the Aiguillette des Posettes (2,202m) and the Flégère ridge (2,360m), with 5,800 metres of total ascent across roughly 90 kilometres. UTMB World Series qualifier. The 23K runs concurrently on a shorter elite-paced course over the Brévent/Flégère ridge.
Sunday June 28 — Marathon du Mont-Blanc (42K) The original race that gave the festival its name. 42 kilometres, 2,600 metres of climbing, finishing on the Plan Praz balcony above Chamonix at 2,000 metres. The men's course record (set on the modern route) is approximately 3:39; the women's is approximately 4:22.
The 2026 Elite Fields
The published elite entry list is, as is now traditional for this race, internationally extraordinary.
90K men's field: Headlining the start list, Jim Walmsley (USA) returns to Chamonix as a defending UTMB champion using the 90K as a final European testing piece before later season targets. Petter Engdahl (Sweden), the long-distance specialist whose 2026 form has been the talk of the European circuit, is entered. Jonathan Albon (Norway/UK), perhaps the most complete obstacle-and-trail athlete of his generation, will race. François D'Haene (France), elder statesman of the discipline and four-time UTMB champion, is entered in what may be one of his final 90K starts at this venue.
90K women's field: Courtney Dauwalter (USA), still the dominant women's ultra-distance athlete on the planet, is entered. Katie Schide (USA/France), the 2025 UTMB winner, races at her local distance. Marianne Hogan (Canada) returns to Chamonix following her 2024 podium here. Manon Bohard Cailler (France), the home-soil contender, brings 2026's strongest French women's form.
Marathon (42K) men's field: Stian Angermund (Norway), three-time Skyrunner World Series champion, is entered. Kilian Jornet (Spain) — and the news that needs to be flagged most prominently — is entered, returning to a Chamonix mass-participation race for the first time since 2022. The course suits him precisely.
Marathon (42K) women's field: Judith Wyder (Switzerland), the multidisciplinary mountain running specialist, headlines. Sara Alonso (Spain) returns from a strong 2025 season. Maude Mathys (Switzerland), the precision-paced veteran, is entered.
KMV (Vertical Kilometer) fields: The vertical kilometer is the most internationally competitive single discipline on the trail-running calendar. The 2026 field includes athletes flying in from skyrunning circuits in Italy, Spain, Slovenia, and Japan specifically for this one event. Henri Aymonod (Italy) and Christel Dewalle (France) headline.
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Join ZealZagFollow us on InstagramWhat Makes This Race Different
The Marathon du Mont-Blanc occupies a specific place in trail running's annual calendar. It is the moment when, every June, the discipline's elite athletes converge in Chamonix not for the late-summer ultra spectacle but for a kind of championship gathering at distances where pace and technical skill matter more than survival across multi-day terrain.
The 90K and Marathon courses are notable for being runnable in their entirety. There is no terrain on these courses that requires technical scrambling. The climbs are relentless but rideable. The descents are steep but consistent. What is being assessed at this race is not whether an athlete can survive — it is who can run fastest across alpine terrain that gives no quarter to inefficiency.
This is also the festival's specific cultural quality: every distance race at the Marathon du Mont-Blanc shares the same competitive atmosphere. The 23K finishers and the 90K finishers share the same finish chute, the same medal, the same post-race food tent. The Mini-Cross competitors run on the same town centre square that, two days later, will host the elite 90K start. The festival is an integrated trail-running culture in a single valley for four days.
Conditions Outlook
Météo France's medium-range forecast for the race weekend currently suggests stable Alpine high pressure: morning lows around 7°C in Chamonix, daytime highs in the mid-twenties at the valley floor, with daytime highs of approximately 12-14°C at 2,000 metres. Some risk of afternoon thunderstorms by Saturday — typical late-June Alpine pattern — which would primarily affect the 90K's mid-race upper-mountain section.
Snowpack on the upper sections of the 90K course has fully cleared. Trails are reported in good summer condition.
The race is, as it always is, ready.
For trail runners planning to experience these mountains themselves, see our Race the Mont-Blanc Marathon route: Chamonix trail running guide.
