What Is UTMB? [Updated August 2025]

UTMB is Europe’s most famous ultramarathon and it’s run as part of the UTMB World Series which also includes CCC and OCC.

Here’s all the most important information you need to know about UTMB. You can jump straight to different sections below.

UTMB (Ultra-Trail du Mont-Blanc) begins and ends in Chamonix, France, and is a single loop circumnavigation of Mont Blanc.

UTMB passes through France, Italy and Switzerland and follows the Tour du Mont Blanc, one of the most popular and famous long-distance walks in Europe.

The main UTMB race covers over 174km (108 miles) with 10,000m of elevation gain.

Several other races take place during the UTMB World Series here, including the 101km CCC and the 57km OCC.

All three races are competitive and attract some of the world’s best ultrarunners as well as amateurs.

UNDERSTANDING THE NAME UTMB

UTMB World is a series of races held all around the world where runners can collect stones and elites can claim their starting place at the UTMB World Series. There are races in different distance categories: 25K, 50K, 100K and 100M.

UTMB World Series is the final of the series circuit, taking place around Mont Blanc with several different races

The main race of the UTMB World Series is called UTMB. Other races include OCC and CCC.

If someone says they are ‘going to UTMB’ it means they will be in and around Chamonix for the UTMB World Series. If someone says they are ‘running UTMB’ then they are doing the big one. Otherwise someone would say there were running OCC, CCC or one of the other races.

UTMB is also the name of the company who organises these races.

WHEN IS UTMB?

In 2025, UTMB World Series takes place from Monday 25 August to Sunday 31 August with different races beginning on different days.

UTMB begins at 17:45 on Friday 29 August. It is 174km. Runners have 46 hours and 45 minutes to complete UTMB.

CCC begins at 09:00 on Friday 29 August 2025. It is 101km. Runners have 26 hours and 30 minutes to complete CCC.

OCC begins at 08:15 on Thursday 28 August 2025. It is 57km. Runners have 14 hours and 30 minutes to complete OCC.

More details on all the other races below

WHAT ARE THE UTMB COURSE RECORDS?

The men’s UTMB course record is held by American Jim Walmsley (19:37:43)

The women’s UTMB course record is held by American Courtney Dauwater (22:30:54)

Why Is UTMB So Famous?

Despite only being run for the first time in 2003, UTMB has become the best-known European ultramarathon, and runners from all over the world dream of entering one of the main UTMB World Series races: UTMB, CCC and OCC. The 174km UTMB is the most famous race and if you hear people talking about UTMB, that’s what they mean.

UTMB is fabled because of its a spectacular and incredibly challenging course which runs through three countries, with epic scenery, brutal climbs, many welcoming aid stations, and the promise of a celebratory atmosphere at the busy finish in Chamonix.

The start and finish in Chamonix has become iconic, especially the playing of Vangelis’s Conquest of Paradise which sends runners off into the mountains.

It’s featured in many great documentaries (this one featuring Jim Walmsley is one of the best), and every year photos and videos of the race reach millions of viewers. For those who love long distance running, it’s very inspiring.

And all of this calls runners to Chamonix to experience it for themselves.

All The UTMB Races Explained!

If you hear UTMB then typically it’s referring to the main 174km route, but over the years other races have been added. In total, around 10,000 runners take part in races at the UTMB World Series Finals.

Here are all the races which are run during the week of UTMB. Apart from ETC, they all finish in Chamonix.

UTMB

WHAT: The UTMB. The main race covering over 108 miles and running anti-clockwise through three countries. DISTANCE: 174km / 108 miles (elevation gain over 9,900m)WHEN: 17:45 Friday 29th August 2025START: Chamonix, FranceRUNNERS: 2,300TIME LIMIT: 46:45

CCC

WHAT: Called UTMB’s ‘little sister,’ though there’s nothing little about this run! The name references three landmark towns on the route: Courmayeur, Champex-Lac, Chamonix.DISTANCE: 101km / 63 miles (elevation gain 6,050m)WHEN: 09:00 Friday 29th August 2025START: Courmayeur, ItalyRUNNERS: 1,900TIME LIMIT: 26:30

OCC

WHAT: UTMB’s 50km, which begins in Switzerland, and takes its name from Orsières, Champex-Lac, Chamonix.DISTANCE: 57km / 35 miles (elevation gain 3,500m)WHEN: 08:15 Thursday 28th August 2025START: Orsières, SwitzerlandRUNNERS: 1,200TIME LIMIT: 14:30

TDS

WHAT: A wilder and more challenging (but shorter) run back to Chamonix. The name is an abbreviation of ‘Sur Les Traces des Ducs de Savoie’ (‘Following the footprints of the Dukes of Savoie’)DISTANCE: 153km / 95 miles (elevation gain over 9,000m)WHEN: 23:50 Monday 25th August 2025START: Courmayeur, ItalyRUNNERS: 1,600TIME LIMIT: 44:55

ETC

WHAT: A challenging loop around the Italian Alps, named as Experience Trail Courmayeur. DISTANCE: 15km / 9 miles (elevation gain 1,200m)WHEN: 14:00 Tuesday 26th August 2025START: Courmayeur, ItalyRUNNERS: 1,000TIME LIMIT: 4:30

MCC

WHAT: A race primarily for locals, volunteers and UTMB partners, but a great flavour of the UTMB experience. The name references Martigny-Combe to Chamonix.DISTANCE: 40km / 24 miles (elevation gain 2,350m)WHEN: 10:00 Monday 25th August 2025START: Martigny-Combe, SwitzerlandRUNNERS: 1,000TIME LIMIT: 10:00

PTL

WHAT: A ‘grand tour’ of Mont Blanc (with a sarcastic name of ‘Petite Trotte à Léon,’ or Leon’s Little Walk, named after Leon Louvey, a baker who organises the Champex-Lac section of UTMB). It’s for more adventurous runners who take part in teams of 2-3. It’s a different route each year and without course markingsDISTANCE: 300km / 186 miles (elevation gain over 25,000m)WHEN: 08:00 Monday 25th August 2025START: Chamonix, FranceRUNNERS: 300 (in teams of 2-3)TIME LIMIT: 151 hours

YCC

WHAT: Two races for youth runners, with distances varying for different ages. The name mean Youth Chamonix Courmayeur.DISTANCE: 15km / 9 miles (elevation gain 1,200m)WHEN: 11:00 Tuesday 26 August 2025START: Courmayeur, Italy and Chamonix, France

The UTMB World Series

The UTMB brand has grown significantly in recent years, and now encompasses the UTMB World Series of trail events all around the world. Each event has several race distances, which are usually (but not always) around 100 miles, 100km, 50km and 25km.

There are more than 50 UTMB World Series Events, plus three UTMB World Series Majors and the UTMB World Series Finals.

How Can You Run UTMB?

Amateurs need to enter a ballot to run one of the three main races – UTMB, CCC and OCC.

To get into the ballot you must have at least one Running Stone and have a valid UTMB index score

Running Stones are earned from UTMB World Series Event races. Typically, a 100-mile race will earn four stones, with three stones for 100km, two stones for 50km and one stone for shorter races.

Runners can collect their Running Stones and the more Stones you have, the better your chance of being successful in the ballot (each stone is one entry).

Running Stones have no expiry and you need to have collected at least one within the previous two years to enter UTMB.

When you enter a ballot, you have to put in all your Stones (so you can’t just choose to use one and save the rest). If you are successful in the ballot, then your number of Running Stones reverts back to zero. In 2024, the average number of Stones for successful runners was five.

A valid UTMB Index means that runners have finished at least one UTMB index race within the past two years. To run the main UTMB race, runners have to have an Index from a 100-mile or 100km race. There are almost 3,000 races worldwide from which you can collect UTMB Index points (and over 250 in the UK). Running a UTMB World Series event will collect you an Index and Stones in the same race.

Elite runners can qualify based on good performances. The top three male and female runners in all UTMB World Series races of 100 miles, 100km and 50km are offered a place at the UTMB, and the top 10 runners in the UTMB World Series Majors get automatic places (though they all still need to pay for their race entry). Runners with a high enough UTMB Index score can also get an automatic qualification in their category.

Runners who finish in the top three at UTMB, CCC and OCC are also offered a place for the following year, as long as they collect at least one Running Stone in the intervening period.