Thursday 15 October, 10 pm local time, Ravine Blanche in Saint-Pierre. When the 34th Diagonale des Fous gets under way, the 2,800 runners will be facing a race none of them has ever run before. For the first time in its history, the Diagonale will not pass through Cilaos. In its place: the Kerveguen, the Caverne Dufour, the Bélouve forest, Hell-Bourg and a reworked crossing of Mafate. In all, 180 km and 10,200 m of elevation gain, making it the longest edition ever raced.
And on this brand-new course, a field that u-Trail describes as “almost as deep as UTMB”: Tom Evans, Ruth Croft, Marianne Hogan, Manon Bohard, Jean-Philippe Tschumi, Beñat Marmissolle. Here is what you need to know before following the race.
The 2026 edition at a glance
| Start | Thursday 15 October, 10 pm — Ravine Blanche, Saint-Pierre |
| Finish | Stade de la Redoute, Saint-Denis |
| Distance | 180 km (175 km in 2025) |
| Elevation gain | 10,200 m |
| Cut-off | 66 hours — last finishers Sunday 18 October |
| Entrants | More than 2,800, a record (3,000 bibs maximum) |
| Edition | 34th |
The Diagonale is the fourth and final major stop of the world ultra-trail season, after Western States, Hardrock and UTMB. For many elites, it is the race that closes out the year; for the island's runners, it is simply the event of the year.
Why Cilaos is disappearing
The decision was made official on 19 February 2026. The organisers cite “traffic constraints linked to the single road access into the cirque”: the Cilaos road and its 400 bends, along with the Gueule Rouge tunnel, created “recurring safety problems” between runners, crew vehicles and spectators. Added to that are the damage left by Cyclone Garance in February 2025, landslides on the trails, and a request from the municipality itself.
Passing through Cilaos was never just an aid station. Reached after 80 km of racing, in the dead of night, it served as a “moment of rebirth”: a life base in a town, warmth, crowds, a bed. The 2026 profile removes that interlude. It is the most profound change to the race in years, and it is what makes predictions so uncertain.
The Trail de Bourbon (100 km), for its part, keeps its start in Cilaos.
The new course, section by section
Saint-Pierre → Mare à Boue. The opening stretch is unchanged: the climb to the Domaine Vidot and Notre-Dame-de-la-Paix, the volcano plateau, then Mare à Boue. It is long, runnable in places, raced at night — the place where races are lost through over-enthusiasm.
The Kerveguen slope and the Caverne Dufour. This is where the 2026 Diagonale branches off. Instead of plunging towards Cilaos, the runners climb via the Kerveguen up to the Caverne Dufour hut, at 2,478 m, below the Piton des Neiges. High point, cold, wind, and no town below to warm up in.
Cap Anglais → Bélouve → Hell-Bourg. The descent via the Cap Anglais, then the Bélouve forest: a primary forest, humid, with slippery roots, which the leaders will probably cross at night or in the early morning. It opens onto Hell-Bourg, in the Salazie cirque, which becomes the race's central life base in place of Cilaos.
Salazie → Mafate. From Hell-Bourg, the course tips over into Mafate via the Sentier Scout and rejoins the cirque's îlets. Those who know the course describe this section as “more punishing” than the old route: more technical climbs and steep descents, without the long runnable stretches that once allowed runners to recover.
Maïdo → Saint-Denis. The exit from Mafate via the Maïdo (2,200 m) remains the race's great wall, followed by the long descent to La Possession, the Grande Chaloupe and the Colorado, before the Stade de la Redoute.
For runners in the pack, the extra 5 km and the more jagged profile represent, according to estimates from specialist sites, 45 to 90 minutes of additional effort. For the elites, the question lies elsewhere: nobody yet knows what a benchmark time looks like on this course.
Men: Tom Evans against the regulars
Tom Evans (34, Great Britain) arrives with the finest record in the field — winner of Western States 2023 and UTMB 2025 — and a 2026 season to salvage. A DNF at Hardrock in July, a withdrawal from UTMB in August: the former British Army officer discovers Réunion with no points of reference, but with the freshness of a man who has not finished a 100-miler this year.
Up against him, two men who know the Diagonale better than anyone:
- Jean-Philippe Tschumi (44, Switzerland) — 2nd in 2022, 3rd in 2023, 2nd in 2024. The eternal runner-up, as regular as clockwork, though his participation remained uncertain in early October.
- Beñat Marmissolle (45, Basque Country) — winner in 2022, six minutes ahead of Tschumi. Out of UTMB 2026 with a foot injury, he won Ultra-Trail Snowdonia this year. He too is listed as doubtful.
Behind them, the outsiders are many:
- Josh Wade (32, Great Britain), 3rd at UTMB 2025
- Hugo Deck (26), two-time winner of the MaXi-Race 100 km, whom we profiled in June
- Thibaut Garrivier, 5th at UTMB 2025
- Gautier Airiau and Léo Rogaume, 2nd and 3rd respectively at the TDS
- Antoine Guillon (56), winner in 2015 and seven times on the podium
And the Réunionnais, racing at home and never to be underestimated on this terrain: Fabrice Payet (40), 6th in 2023 and 2025, first local finisher last year in 25:42, who is targeting 25 hours; Judicaël Sautron, a top-10 regular; Nicolas Rivière, 2nd in 2019.
Women: Ruth Croft, hot favourite on her debut
Ruth Croft (37, New Zealand) is the reigning UTMB champion, having won in 2025 after finishing 2nd in 2024. She withdrew from Chamonix two days before the start this year. This is her first Diagonale, and she has warned on social media that she wants to “do the race justice” by giving “the very best” of herself.
Her main rival may well be Marianne Hogan (36, Canada). Second at UTMB in 2022, third in 2024, she was running 2nd at the 2025 Diagonale before dropping out with a calf injury. She returns off the back of a 3rd place at Western States in June.
Then comes local knowledge: Manon Bohard (35), winner in 2024, took the Restonica Trail and the Échappée Belle in 2026 and says she has “the deep conviction” that her body is “more functional today than in 2024”. Sarah Vieuille, 4th in 2025, arrives with a win at the TDS (22:08). Émilie Maroteaux (46), from Réunion, won in 2021 and finished 3rd in 2023. And Claire Bannwarth, the insatiable, lines up again after a 5th place at the Tor des Géants three weeks ago.
The big absentees
The list is long, and it partly explains why the race is so open:
- Baptiste Chassagne, 2025 winner in 23:31:54, made UTMB his priority — and finished 2nd there in 18:47
- Blandine L'Hirondel, 2025 winner, followed up with a victory at UTMB
- Ludovic Pommeret, 2021 winner, recently underwent foot surgery
- Aurélien Dunand-Pallaz, 2023 winner, has gone off to attempt the GR20 record
- Mathieu Blanchard, 2024 winner, out with a heel injury
- Courtney Dauwalter, holder of the women's benchmark since 2022 — 24:37:47, 4th overall
On that last point, one detail matters: since the course has changed, every race record starts again from zero. The 2026 winner's time will, by definition, be a record.
What will decide the race
The night without Cilaos. The leaders will pass the Caverne Dufour and Bélouve in the heart of the first night, without the mental respite of the old life base. Those who built their strategy around “holding on until Cilaos” will have to reinvent it.
The heat in Mafate. The second day is run inside the cirque, often above 30 °C at the bottom of the ravines. It is where runners arriving from Europe at the end of their season pay the highest price.
Experience of Réunion's terrain. The island's trails — steps, roots, mud, volcanic rock — are like nothing in the Alps. Tschumi, Marmissolle, Bohard and Payet know it. Evans and Croft are about to find out.
Freshness. Evans and Croft have not finished an ultra this summer. Hogan is coming off Western States, Vieuille off the TDS, Bannwarth off the Tor. Over 180 km, fresh legs count as much as a track record.
How to follow
Live tracking is provided on the Grand Raid website and by Réunion la 1ère, which broadcasts the race continuously. The first men are expected in Saint-Denis during the day on Saturday 17 October, after around 23 to 25 hours of racing; the first women a few hours later. The last finishers will cross the line on Sunday 18 October before 4 pm local time, at the end of 66 hours.
To understand the format and logic of the great 100-mile races, read our features on Western States, Hardrock and UTMB.
Main sources: Grand Raid de La Réunion · Outside.fr · Réunion la 1ère · u-Trail · Référence Trail · Extérieur Sport