La Diagonale des Fous 2026: preparation, logistics and gear guide

The Diagonale des Fous is one of the five races organised as part of the Grand Raid de La Réunion. It crosses the heart of the island, from south to north, through the Réunion National Park listed as UNESCO world heritage — peaks, cirques and ramparts.

The start is in the south, on the Ravine Blanche site in Saint-Pierre, place Salahin, on Thursday 2026-10-15 at 22:00. Runners therefore set off in darkness, on head torches, and the finish is judged at La Redoute, in Saint-Denis.

The official cut-off table gives the complete profile: 180.8 km in total, 10,191 metres of cumulative climbing and 10,154 metres of descent. The race page block, meanwhile, announces 180 km and 10,200 m — this guide uses those figures, while naming both sets.

The route is not a sequence of long regular climbs: it alternates re-ascents of several hundred metres and descents that give everything back, from sea level to 2,475 metres at the Croisée Coteau Kerveguen, then almost back to sea level at the Ilet Savannah, at kilometre 140.5, before a last series of bumps up to Saint-Denis.

Two life bases punctuate the course: Hell-Bourg at kilometre 80.6, roughly halfway, and the Ilet Savannah at kilometre 140.5. The cut-off table adds fourteen further checkpoints with eliminating cut-offs and thirteen waypoints whose timing is indicative.

The race rules, as the race page reproduces them, strictly forbid the use of any pole of any kind, on pain of sanctions. That is a feature of this race to take on board very early in preparation.

The first number to look at is not the distance, it is the time limit: 66 hours. A runner aiming at the end of the cut-offs spends two full nights and part of a third one moving. Preparation must include at least one long night outing, and preferably one that runs into a second night.

The climbing-to-distance ratio is 57 metres of ascent per kilometre, but it is unevenly spread. The cut-off table shows the first half much steeper than the second: 4,043 metres of cumulative climbing at kilometre 80.6, and already 7,969 at kilometre 123.9. Training for the average means training for a different race.

The hardest sections are not the longest. Between Mare à Boue at kilometre 55.6 and the Croisée Coteau Kerveguen at kilometre 67.6, the course gains 996 metres in twelve kilometres and rises to 2,475 metres; between the Ilet Savannah and the finish, 40 kilometres and nearly 2,100 metres of climbing remain, on fifty-hour-old legs.

Since poles are forbidden, all the climbing work is done without them. A preparation that uses them on long runs trains a support the race will not allow: better to do the climbing volume empty-handed, so that quadriceps and calves get used to absorbing it alone.

The descent is the second half of the problem: 10,154 metres of descent, much of it on island trails that alternate roots, steps and rocks. Long technical descents at the end of a long run, when alertness drops, are the session that most resembles kilometre 150 of the race.

Finally, the climate: the race is run in October on Réunion, and the organisers' page insists on changing weather, rivers to cross and varying altitude. The mandatory kit follows from that — a waterproof jacket with taped seams, a windproof being explicitly ruled out as insufficient protection.

The start pen opens on Thursday 2026-10-15 at 18:00 at the Ravine Blanche, in Saint-Pierre, and closes at 22:00 — the start time. It is the first line of the cut-off table, and it works like the others: after 22:00, you do not start.

The finish is at La Redoute, in Saint-Denis, at kilometre 180.8. Its barrier opens on the Friday at 19:00 and closes on the Sunday at 16:00, which gives the 66 hours announced on the race page.

Two life bases: Hell-Bourg at kilometre 80.6, whose barrier closes on the Saturday at 01:00, and the Ilet Savannah at kilometre 140.5, which closes on the Sunday at 00:15.

The entry price is 260 €, and the organisation announces 3,000 participants maximum.

The official cut-off table carries, station by station, columns for the drop bag, personal assistance, aid station, soup and hot meal, as well as for the presence of a doctor, nurse, physiotherapist, podiatrist, osteopath and first-aider. The station-by-station values are not reproduced here: they are read on the official document, in colour and in columns, and are easily mis-read a line out.

The page also announces the presence of ambulances and of the Croix Blanche in the medical arrangements.

Reconnaissance between Bassin Plat and Piton Sec is strictly forbidden: that land is private. The organisation says so in capitals on the race page.

The page finally carries an explicit warning: it is being updated, and the route may be changed for administrative or practical reasons, or because of the state of the trails. Since some sections are only accessible at race time, it is the official document of the day that counts.

The Diagonale des Fous is a crossing, not a loop: it starts from the Ravine Blanche, in Saint-Pierre, in the south of the island, and finishes at La Redoute, in Saint-Denis, in the north. Start and finish are therefore at two ends of Réunion, which is the first logistical constraint to settle, even before accommodation.

The official course description starts at the place Salahin, on the Ravine Blanche site, then takes the boulevard Hubert De Lisle to the Terre Sainte seafront, rue Amiral Lacaze, before leaving town at the croix Jubilé roundabout by the road of the same name, towards the Bassin Plat junction.

The official site does not publish, on the race page, any shuttle plan between Saint-Denis and Saint-Pierre: that information is to be looked for in the organisation's practical information, not here.

The race page publishes no accommodation list and no hotel partnership: this guide invents none. For everything beyond the race itself, the organisation points to its practical information and to its section about Réunion.

The only constraint the route imposes is geographical: the day before happens in Saint-Pierre, in the south, and the end of the race in Saint-Denis, in the north. Accommodation booked on only one side of the island forces a transfer to the other end, with arrival times that can spread over more than two days depending on pace.

The two life bases, Hell-Bourg at kilometre 80.6 and the Ilet Savannah at kilometre 140.5, are the points where the organisation lays on facilities during the race; they, rather than any accommodation, are what structures sleep during the event.

The Diagonale des Fous is prepared from two numbers and one ban: 66 hours of time limit, 10,200 metres of climbing, and no poles. The first two dictate sleep and nutrition; the third dictates how you climb, and it has to be taken on board months in advance.

The official cut-off table is the document to know by heart: for each of the sixteen checkpoints it gives the hour at which the race ends. It is published as a PDF on the race page, and it, not a guide, is what counts on the day — all the more so as the organisers announce the route may still change.