Val d'Aran by UTMB
Termières dera Libertat (TDL 75K)
Bossòst → Vielha
Race guide
Updated 19 July 2026
The Termières dera Libertat (TDL 75K) is a point-to-point mountain ultra that forms part of the Val d'Aran by UTMB race weekend in the Pyrenees. Starting in Bossòst at 714 m and finishing in Vielha at 971 m, the route covers 75 km with a demanding 4858 m of total ascent, reaching a high point of 2456 m somewhere along its mountain traverse. The net elevation change between start and finish is modest, but that figure is deeply misleading — nearly 5000 m of climbing packed into 75 km means this race belongs firmly in the demanding category, demanding respect for both its vertical and its total distance. The point-to-point format from Bossòst to Vielha means you are always moving through new terrain, threading through the Val d'Aran's characteristic high ridges and valley systems. With crew access at both the start and the finish, and a single hard cut-off of Thursday 04:00 at the finish in Vielha, race management is relatively straightforward — but that also means you must carry everything you need and manage your effort precisely across the full 75 km without mid-race crew support in between.
Course & Terrain
The TDL 75K runs point-to-point from Bossòst (714 m) to Vielha (971 m) through the Val d'Aran, a Pyrenean valley system straddling the Catalan side of the range. The route climbs to a high point of 2456 m, which means you will be spending meaningful time above 2000 m on exposed mountain terrain. With 4858 m D+ across 75 km, the average gradient of the climbing sections is consistently steep — expect few flat kilometers as a genuine rest. The terrain in Val d'Aran typically blends forest singletrack in the lower valley sections with open alpine ridgelines, rocky cols, and grassy slopes at higher elevations. Footing can vary significantly between smooth woodland paths and technical rocky ground near the high point, so trail shoes with reliable grip across multiple surfaces are essential.
The Decisive Climbs & Descents
With a high point of 2456 m and a start elevation of just 714 m, the route demands at least one very long, sustained ascent early in the race, gaining well over 1700 m of net elevation before the terrain can begin descending toward the high point. The nature of the 4858 m total climb distributed across 75 km suggests multiple significant ascents and descents throughout the course rather than a single big push. The highest sections at and around 2456 m are where the race often exposes runners who have gone out too hard — altitude slows everyone slightly and the exposure can add a psychological challenge. The descents back toward Vielha at 971 m are long, and technical footing on the way down will test quad durability late in the race. Protect your quads on every descent from the first; the final run into Vielha demands that you still have legs.
Pacing Strategy
With no intermediate crew points between Bossòst and Vielha, your pacing plan must be self-contained from the gun. The point-to-point format removes the psychological anchor of returning to a familiar base, so managing effort on the early climbs is critical. Given 4858 m D+ over 75 km, a useful rule of thumb is to hike all steep ascents from the very start — even if you feel strong — and reserve running for flatter and downhill sections. The single finish cut-off of Thursday 04:00 in Vielha gives you a fixed time window; calculate your required average pace against that deadline and check in with it mentally at regular intervals throughout the race. There is no safety net of a mid-race cut-off to act as an early warning, so runners must self-regulate. Budget extra time for the high-altitude sections around 2456 m where pace naturally drops.
Fueling & Hydration
With crew access only at the start in Bossòst and the finish in Vielha, you must carry all your nutrition or rely entirely on any race-provided aid along the course. Plan your calorie and hydration strategy to be self-sufficient across the full 75 km. At this distance with nearly 5000 m of climbing, most runners will be on course for many hours — fueling early and consistently, before hunger or thirst set in, is essential. High-altitude sections above 2000 m can suppress appetite while simultaneously increasing caloric demand, so practice eating when you do not feel hungry. Electrolyte management matters on a race this long; Pyrenean summers can bring warm temperatures in the valleys and much cooler, windier conditions at the high point, which complicates sweat rate prediction. Carry capacity for enough fluid to bridge the gaps between any water sources on course.
Conditions to Expect
Val d'Aran sits in a unique microclimate among the Pyrenees, influenced by Atlantic weather systems from the north as well as Mediterranean conditions from the south. This means weather can be highly changeable — a warm, sunny start in Bossòst does not guarantee similar conditions at 2456 m. Afternoon thunderstorms are a real possibility in the summer mountain racing season, and the high point is fully exposed to any incoming weather. Carry a waterproof jacket and mandatory kit regardless of the morning forecast. Temperatures in the lower valley sections can be warm to hot, while the high ridges will be considerably cooler and potentially windier. Starting in Bossòst at 714 m and finishing in Vielha, runners may also be navigating portions of the course in darkness given the race's extended time window, so a reliable headlamp with spare batteries is non-negotiable.
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Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-05) · official source
0 km · 713 m · —
7.6 km · 1299 m · Wed 10:00
17.6 km · 2001 m · —
26 km · 1472 m · Wed 15:00
40.5 km · 1600 m · Wed 18:20
53 km · 1398 m · Wed 21:30
66.6 km · 1783 m · Thu 02:00
74.8 km · 970 m · Thu 04:00
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