The Tour de France serves up its hardest stage of 2026 on Saturday, 25 July — a 170.9-kilometre mountain marathon from Le Bourg d'Oisans to l'Alpe d'Huez that crosses four categorised climbs and gains 5,450 metres of elevation before it is done The Guardian, letour.fr.

Three of the four climbs are hors catégorie — the rating given to mountains too tough to fit into the normal grading system. They are the Col de la Croix de Fer, the Col du Galibier, and the Alpe d'Huez approached via the Col de Sarenne The Guardian.

The stage opens with the Croix de Fer, a 24-kilometre slog averaging 5.2 per cent, its summit reached just 33.7 kilometres after the start The Guardian, letour.fr. Riders then descend through Saint-Jean-de-Maurienne and Saint-Michel-de-Maurienne before the Col du Télégraphe, whose summit falls 87.6 km in. That feeds directly onto the Galibier — at 2,642 metres the highest point of the entire 2026 Tour letour.fr, letour.fr.

The finish is the one every cyclist knows: Alpe d'Huez. But this year the climb comes the back way, via the Col de Sarenne on its south-eastern flank — a narrow, environmentally sensitive road that drew protests from local ecologists over the race passing through The Guardian, letour.fr. The Guardian's William Fotheringham called Stage 20 "the hardest stage of the Tour" — potentially decisive for the overall standings or a final reshuffle of the order The Guardian.

Tadej Pogačar wears the yellow jersey — the garment given to the race's overall leader — and had already locked down a dominant lead before the stage. Jonas Vingegaard sits alongside him with what was described as "an iron grip on the race." Pogačar set a record-breaking ascent of Alpe d'Huez on Friday's Stage 19 and said his focus for Stage 20 was helping teammate Isaac del Toro secure the young rider's classification — the white jersey competition for the best-placed rider under 26 The Guardian.

Behind the two leaders, Paul Seixas was in contention for a podium place in the overall classification The Guardian. A reshuffle on the Galibier or the Sarenne could reshape who stands on the Champs-Élysées podium in Paris.

The racing began early. An original six-rider breakaway — Baptiste Veistroffer, Joris Delbove, Jonas Abrahmsen, Warren Barguil, Xabier Azparren and Georg Steinhauser — formed after three kilometres The Guardian. By 151 km remaining, a larger lead group of 15 had coalesced, including Richard Carapaz, Valentin Paret-Peintre, Juan Ayuso and Sepp Kuss. The peloton — the main pack of riders — trailed by 33 seconds at 157 km to go.

Mads Pedersen, who had won just one stage but held the green jersey (the points classification) thanks to strong intermediate sprint results, lost ground on the climbs The Guardian. Mountain stages rarely suit the sprinters, and the parcours here is unforgiving.

What makes this stage stand out is the sheer weight of climbing packed into fewer than 171 kilometres. The Croix de Fer alone is a Grand Tour climb in its own right. Add the Galibier at altitude and the Sarenne's awkward, narrow approach to Alpe d'Huez, and the route offers very little flat road and no place to hide.