TDS is a 145km ultra marathon in Courmayeur, Italy. Distance: 145km. Elevation: 9,100m D+. Difficulty: brutal (Challenge Rating 66/100). DNF rate: 30%. Time limit: 40h. Surface: trail. Established 2007.
TDS
Courmayeur, Aosta Valley, Italy
"145km from Italy to France on ancient Savoyard routes — the wildest and most technical race in the UTMB festival."
The wild sibling of UTMB — 145km from Courmayeur to Chamonix through remote alpine terrain that many consider the finest mountain ultra in the UTMB festival.
The Course
From Courmayeur, Italy to Chamonix, France — the wildest and most technical race in the UTMB festival. The course follows ancient routes of the Dukes of Savoy through remote valleys, technical alpine terrain, and high mountain passes. Less crowded and more wilderness-oriented than UTMB itself.
mountainous
point-to-point
9
2,600m
6
Runner Experience
UTMB-standard aid stations with hot food, drinks, medical support, and drop bag access at major checkpoints.
Professional UTMB-style finish with crowds, announcements, and a festival atmosphere in the finish area.
Race Day Weather
10°C
060%
40%
Late August Alpine weather. Cold at altitude, pleasant in valleys. Night sections through high terrain are genuinely cold.
Stats & Records
2007
1,000
28:00:00
14:22:15
Dmitry Mityaev (2022)
17:35:22
Blandine L'Hirondel (2023)
Entry
€230
December
instant
Lore & Trivia
TDS (Sur les Traces des Ducs de Savoie) is the wild card of the UTMB family — 145km with 9,100m of gain through the most remote and technical sections of the Mont Blanc massif. While UTMB and CCC follow well-worn trails, TDS deliberately seeks out the paths less travelled: high alpine passes, exposed ridgelines, and sections where the trail is more suggestion than reality. The route traces the historical boundaries of the Duchy of Savoy through terrain that demands genuine mountain skills — route-finding, scrambling, and comfort with exposure. TDS attracts a specific type of runner: mountain athletes who find groomed trails boring and want their ultra to feel like an adventure, not a parade.
- ▸ 145km with 9,100m of gain — more technical than UTMB itself.
- ▸ Traces the historical borders of the Duchy of Savoy.
- ▸ Part of the UTMB event week but attracts mountain purists over trail racers.
- ▸ Several sections require scrambling and route-finding skills.
- ▸ The most remote of the UTMB races — long stretches without spectators.
- ▸ Often considered the connoisseur's choice of the UTMB family.
- ▸ Higher exposure and more technical terrain than CCC or UTMB.
TDS is what UTMB would be if it went feral. Same mountains, none of the crowds, twice the adventure.
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Frequently Asked Questions
How long is TDS? +
TDS is a 145km (145km) ultra marathon with 9,100m of elevation gain. The course is point-to-point on trail terrain.
How hard is TDS? +
TDS is rated brutal with a Challenge Rating of 66/100 (Demanding). The DNF rate is 30%. Runners have 40 hours to finish.
How do I enter TDS? +
UTMB Index qualification through UTMB series races. Entry is by lottery. Entry costs €230. with a maximum of 1500 starters.
What is the weather like at TDS? +
Average temperature is 10°C with 60% humidity and a 40% chance of rain. Late August Alpine weather. Cold at altitude, pleasant in valleys. Night sections through high terrain are genuinely cold.
Are crew and pacers allowed at TDS? +
Crew access is allowed. Pacers are not allowed. Mandatory gear is required.
What is the course record for TDS? +
The men's course record is 14:22:15 set by Dmitry Mityaev in 2022. The women's course record is 17:35:22 set by Blandine L'Hirondel in 2023.
What is the average finish time for TDS? +
The average finish time is 28:00:00. About 1,000 runners finish each year. The DNF rate is 30%.
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