The wildest, most technical long race of UTMB week, from Courmayeur through the Beaufortain
Other trail races within 69 miles
Named for the Dukes of Savoy, the TDS links Italy's Aosta Valley to the Savoie and is widely seen as the most technical long race of the week. It starts in Courmayeur just before midnight on Monday, climbs past Lac Combal and the Col Chavannes, drops to La Thuile and the Petit-Saint-Bernard, and descends to Bourg-Saint-Maurice. From there it climbs to the Fort de la Platte and the Passeur de Pralognan and crosses the remote Beaufortain — Cormet de Roselend, Pas d'Outray, Beaufort and Hauteluce — before Les Contamines, the Col de Tricot, Les Houches and the finish in Chamonix. Only about 60% of starters finish.
Recommended for seasoned ultrarunners
Chamonix, Haute-Savoie, FranceAugust 24, 2026
TDS – Sur les Traces des Ducs de Savoie is a point-to-point trail race in Chamonix, Haute-Savoie, France, held on August 24, 2026. The course covers 145 km, climbs 9,332 m, and has a 44h55m cutoff.
Must complete a 100K race or longer within the qualification window
A valid UTMB Index in the 100K or 100M category is required.
| Location | km | Elevation | Cutoff | Crew | Drop bags |
|---|---|---|---|---|---|
Start Start | 0.0 | 1,223 m | — | ||
Finish Finish | 145.0 | 1,035 m | 44h55m8:45 PM +2 |
Aid station details for this race are still being filled in. Cutoffs and access rules come from the race’s own published information and can change — check the official race details before planning around them.
Sign in for race-day weather at every station, points of interest, segment-by-segment analysis, pacing, and to save this race to your calendar.
Runners may not take part with a dog or any other animal, including service animals.
Late August around Mont-Blanc can bring anything. The valleys (Chamonix about 1,035 m, Courmayeur about 1,220 m) often see 20–30 °C days, while the passes above 2,000 m can drop below freezing at night, and the organizers warn of temperatures down to −10 °C, with rain, hail or snow possible. Afternoon thunderstorms are common, and weather can force course changes or delays.
Two nights out for most runners on passes above 2,500 m
Afternoon storms on exposed cols in the Beaufortain
![Video thumbnail: [UTMB 2025] Marine Quintard et Mathis Dumas : retour sur la MCC](https://img.youtube.com/vi/k1jWtpkQ6aA/hqdefault.jpg)
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