My marathons

Marathon du Mont Blanc

The organiser has not published a date. Chamonix-Mont-Blanc
Chamonix
Chamonix. Photograph by Tiia Monto, CC BY-SA 3.0 via Wikimedia Commons

The course

The organiser's flagship 42 km course has 2,540 m of positive and negative elevation, fast rolling trails early and the steep, technical slopes of the Aiguillette des Posettes as its main difficulty.

The course in short 3 lines
  • A 42 km mountain trail with 2,540 m of climbing and descent42 km, 2,540 m up and down; the Aiguillette des Posettes is the hard part.
  • 2,300 runners, six waves and a 10-hour limitLimited to 2,300 runners, six waves, 10 hours maximum, compulsory kit.
  • A Sunday start in Chamonix, finish off the Triangle de l'Amitie2026: elite women 6:45, elite men 7:15, then the rest; first finishers 10:45.
Course notes 3 short reads on the course
Whole courseGradientA 42 km mountain trail with 2,540 m of climbing and descent42 km, 2,540 m up and down; the Aiguillette des Posettes is the hard part.

It ends facing the Mont Blanc range. The organiser warns that a runner with a UTMB performance index under 350 points has very little chance of finishing and recommends mountain-running experience and the ability to be self-sufficient for several hours. The course has three full aid stations plus one at the finish.

Sourced

Whole courseConditions2,300 runners, six waves and a 10-hour limitLimited to 2,300 runners, six waves, 10 hours maximum, compulsory kit.

The organiser’s compulsory kit for the 2026 edition was a working mobile phone, at least 1 litre of water, a hooded waterproof jacket, a survival blanket, a cup, a whistle and cash, and bibs were only handed out against the kit.

Sourced

Whole courseLandmarkA Sunday start in Chamonix, finish off the Triangle de l'Amitie2026: elite women 6:45, elite men 7:15, then the rest; first finishers 10:45.

The 2026 weekend ran from Thursday 25 to Sunday 28 June, with the 90 km on Friday, the 23 km and 10 km on Saturday and the 42 km prize-giving at 5:00 PM on Sunday. The organiser announces the 2027 edition for 24 to 27 June in Chamonix.

Sourced

Race fuel

Energy gel
An energy gel sachet
Illustration · drag to turn

Race fuel for Chamonix-Mont-Blanc

One gel every 40 minutes once you are past about 75 minutes of running, plus a spare.

Our pick: SiS BETA Fuel gel, box of 6, strawberry and lime. 40 g of carbohydrate a gel, about twice a usual gel, from two kinds of sugar your body takes up side by side.

Easy to forget on race morning: pack them with your bib the night before.

Get it on Amazon

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In Canada the button opens GU Energy Gel, Salted Caramel, 24-pack, the best seller there.

Outside the Netherlands, Belgium, Germany, Austria and Switzerland, the UK and Ireland, Spain and Portugal, Italy, the rest of the EU and Canada the button opens GU Energy Gel, Chocolate Outrage, 24-pack on Amazon.com, the best seller there.

Anti-chafe
Compeed Anti-blister stick
Photo: Compeed

Compeed

Compeed anti-blister stick, 8 ml

Best selling on Amazon amazon.nl, read 2 Nov

An invisible layer before the start keeps seams, straps and shoes from rubbing skin raw.

Put it on before you leave for the start: heels and toes, inner thighs, under a bra or heart-rate strap.

Try it on a long run first, like everything you use on race day.

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We earn a small fee if you buy through these links. The price is the same.

Number belt
A race number belt
Illustration · drag to turn

Compressport Race Belt

Holds your bib without safety pins through your top, with loops for up to 8 gels.

Clip the bib on the night before, so it goes on with your shorts in the morning.

Keep the number on the front, where officials and photographers can see it.

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We earn a small fee if you buy through these links. The price is the same.

Electrolytes
A tube of electrolyte tablets
Illustration · drag to turn

SiS Hydro electrolyte tablets, tube of 20

One tablet in a bottle puts back some of the salt you sweat out.

One tablet in 500 ml of water in the hour before the start.

Only if you have used them in training: nothing new on race day.

Get it on Amazon

We earn a small fee if you buy through these links. The price is the same.

Blister plasters
Compeed Blister plasters, medium, 6
Photo: Compeed

Compeed

Compeed blister plasters, medium, 6

Best selling on Amazon amazon.nl, read 2 Nov

One in a pocket cushions a blister if one starts.

Put it on clean, dry skin and leave it until it comes off by itself.

Give a couple to whoever comes to cheer, so they are there at the km you need them.

Get it on Amazon

We earn a small fee if you buy through these links. The price is the same.
race
Running event

Trip

Getting a place

Entry through the organiser

montblancmarathon.net: this address now sends you somewhere else, so it is not linked.

The organiser, a third party. We take no entries and have no part in the race.

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