Trail guide · Réunion, France
Diagonale des Fous 2027 training guide: qualifying, terrain, kit
Across Réunion from Saint-Pierre to Saint-Denis: 180 km and 10,200 m of climbing in 2026, through the cirques of the National Park, with 66 hours to finish. You have to qualify first, and the terrain is slower than anything in the Alps.
OpenAthlete is not affiliated with the organisers. This is an independent preparation guide.
Key facts
2027
- Date
- 2027 date not announced yetEvery October, mid-month (15–18 October in 2026). The 2027 dates are not announced yet.
- Start
- Thursday 22:00 from Saint-Pierre in 2026, at night
- Distance
- 180 km
- Elevation
- +10,200 m
- Time limit
- 66 hours
- Course
- Point to point across the island, from Saint-Pierre to the Stade de La Redoute in Saint-Denis, through the cirques of the Réunion National Park: very technical volcanic trails, steps, rocks and roots. The route can change.
- Usual weather
- October on the coast: 20 to 27 °C on average (Météo-France normals, Saint-Denis). Cooler and changeable at altitude, especially at night.
Facts checked on 4 November 2026. Organisers change things: confirm on the official site before you book anything.
The course, seen by a coach
Diagonale des Fous: what it asks of you, and how to train for it
Slower per km than the Alps
Steps, roots and wet volcanic rock make the time per km far slower than in the Alps for the same climbing. Train on the worst ground you have: stairs, rocky paths, steep forest. Add step-ups and step-downs with a loaded pack twice a week, and forget pace: judge long days by hours and climbing.
Heat below, cold above
The coast is tropical, the high ground is cool and changeable, and the start is at night. Train with the full kit in your pack, test your rain layer in real rain, and do a few long runs in the heat of the day if you come from a cooler climate.
Qualify first
The regulation asks for two finished races of at least 85 km-effort points each (1 km = 1 point, 100 m of climbing = 1 point) within a set period. Put them in your season on purpose: they are your longest training days, so space them at least two months apart and recover from each.
Training plan
No ready-made plan for the Diagonale des Fous, honestly
Our trail plans stop at 50 km. Past that, a generic plan for 180 km would be guesswork: your past races, your terrain at home and your weeks matter more than any template. Use the 50 km plan as a stepping stone the season before, then build the long block with a coach or in your own calendar.
The race in km-effort
282km-effort
- Diagonale des Fous180 km · +10,200 m
- Our 50 km plan race50 km · +2,500 m
- Road marathon42.2 km · 0 m
180 km + 10,200 m ÷ 100 = 282 km-effort, 3.8 times the race our 50 km plan prepares. Enter 180 km and 10,200 m in the trail time estimator with a recent race to get a finish window.
What the preparation must include
Four things no long trail forgives you for skipping
Back-to-back long days
Four to six weekends before the taper, run long on Saturday and again on Sunday on tired legs: 4 h then 3 h, on terrain like the race. It teaches the legs and the stomach to keep going without one 8-hour run that wrecks a week.
Night running
Run with your race headlamp at least three or four times, on trails, after dark. Footing is slower, sleepiness hits around 3 am, and you want to know your battery life before the race tells you.
Poles and power hiking
On long climbs, most runners walk. Train it: 20 to 40 min of steep uphill hiking with poles, once a week. If poles are allowed and you plan to use them, never race with them for the first time.
Descents
Quads fail on the way down, not up. Run long downhills every week from three months out, add step-downs and lunges, and practise technical ground at an easy pace until it feels boring.
Build the block in OpenAthlete: plan the back-to-back weekends in the calendar, write the hill sessions once, and send them to your Garmin, COROS or Suunto watch.
Plan it for freeDiagonale des Fous: questions runners ask
The regulation asks for two finished single-stage foot races of at least 85 km-effort points each (1 km = 1 point, 100 m of climbing = 1 point) within a set period, plus a medical certificate or licence. In 2026 the entry fee was €260 and the field was capped at 3,000 runners.
Not announced on 4 November 2026. The Grand Raid is held every October, around the middle of the month: in 2026 it ran from 15 to 18 October, with the Diagonale starting on Thursday at 22:00.
Count six to nine months of specific work on top of a solid trail base, and at least one long race (50 km or more) the season before. The last 12 to 16 weeks carry the big weekends and the night runs; the last two or three weeks are a taper.
No. OpenAthlete is not affiliated with the organisers of Diagonale des Fous. This is an independent preparation guide written from the official information available on 4 November 2026. Registration, rules and the final course are on the official site.
Prepare the Diagonale des Fous with the plan on your watch
Import a free plan into OpenAthlete, move sessions around your week, and send them to your Garmin, COROS or Suunto watch. Everything is free on Cloud.
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