Your plan in four answers
Mont-Blanc Marathon has not announced its next date, so we have estimated June. Change the date below once you know it.
- Distances
- 10K, 23K, Marathon, 88K
- Terrain
- Hilly
- Field
- About 10,000 runners across eight races; the 42 km is capped at 2,300
Course
The Mont-Blanc Marathon course
The 42 km is a mountain trail marathon with about 2,540 m of climbing and the same again in descent, starting in Chamonix at Place du Triangle de l'Amitié. The route runs up the valley to Le Tour (km 13.5), crosses to Vallorcine (km 23.5), then climbs the Aiguillette des Posettes, the steep and technical crux of the day.
Read the full course notes
From there it traverses the balcony trail to La Flégère (km 34.2) facing the Mont-Blanc massif before the long drop back into Chamonix. Expect singletrack, roots and rock rather than road, and a 10-hour limit from each start wave. The field is capped at 2,300 runners, and the weekend also offers a 10 km, a 23 km and an 88 km ultra branded as the 90 km.
- Terrain
- Hilly
- Distances
- 10K, 23K, Marathon, 88K
- Field
- About 10,000 runners across eight races; the 42 km is capped at 2,300
- Weather on race day
- Late June in Chamonix usually brings mornings around 7–10 °C in the valley and afternoons up to about 21 °C, cooler on the high balconies near 2,000 m. Mountain showers and thunderstorms are common in June, and the sun is strong at altitude, so carry a light shell, drink to thirst early and expect your pace to drop well below road pace on the climbs.
What to train for
Train for hours on feet and vertical metres, not kilometre splits: build to weekly long days of 4–6 hours with 1,500–2,000 m of climbing.
Practise power hiking with or without poles on steep grades, because the Posettes are walked by almost everyone.
Rehearse long technical descents of 800 m or more so your quads survive the final drop from La Flégère to Chamonix. The organisers note that an UTMB index below 350 leaves little chance of finishing, so use a hilly trail race of 25–35 km as a fitness test about six weeks out.
Sample week
A sample Mont-Blanc Marathon training week
A week from the middle of the build, about six weeks out. Your plan sets the real distances and paces from your own fitness and adjusts them every week as you train.
- Monday
- Rest, or 20 minutes of mobility
- Tuesday Key session
- Hill repeats: 10 × 90 s up a steady grade, jog back down
- Wednesday
- Easy run, 10–11 km
- Thursday Key session
- Goal-pace run, 16 km with 10 km at race pace
- Friday
- Recovery run, 6 km, or cross-train
- Saturday Key session
- Long run, 26–29 km on hilly ground, steady effort on the climbs
- Sunday
- Easy run, 6 km, then 6 relaxed strides
Taper
Tapering for the Mont-Blanc Marathon
Start the taper two to three weeks before race day. Cut your weekly volume by about a third, then by half in race week, and keep a few short efforts at race pace so your legs stay sharp. The course is hilly, so keep one short hill session in the first taper week to keep the climbs familiar.
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Build me a training plan for the Marathon du Mont-Blanc in June. I run [distance] a week, [days] days a week, easy pace [pace].
Mont-Blanc Marathon training questions
How long should I train for the Mont-Blanc Marathon?
Most runners give a marathon sixteen to twenty weeks of focused training on top of an existing base. The plan above counts back from your actual race date, so if you have less time than that it builds the best plan the remaining weeks allow rather than pretending you have longer.
Is the Mont-Blanc Marathon course hilly?
Hilly. The 42 km is a mountain trail marathon with about 2,540 m of climbing and the same again in descent, starting in Chamonix at Place du Triangle de l'Amitié.
What is the weather usually like at the Mont-Blanc Marathon?
Late June in Chamonix usually brings mornings around 7–10 °C in the valley and afternoons up to about 21 °C, cooler on the high balconies near 2,000 m. Mountain showers and thunderstorms are common in June, and the sun is strong at altitude, so carry a light shell, drink to thirst early and expect your pace to drop well below road pace on the climbs.
When should I start tapering for the Mont-Blanc Marathon?
Start the taper two to three weeks before race day. Cut your weekly volume by about a third, then by half in race week, and keep a few short efforts at race pace so your legs stay sharp. The course is hilly, so keep one short hill session in the first taper week to keep the climbs familiar.
Do I need an account to get a Mont-Blanc Marathon training plan?
No. The plan above builds in your browser with no account, no email, and no card. Make a free account only if you want to keep it, log your runs against it, and have the coach keep adapting it as your training goes.