Every year at the end of August, the world’s elite trail runners come to Chamonix for a week of endurance racing. The week of the UTMB® Mont-Blanc (Ultra-Trail du Mont-Blanc) includes several individual races and a team challenge — and the distances are truly epic.
The runners cross three countries, seven valleys, 71 glaciers and around 400 mountain summits, with the flagship UTMB® race covering approximately 170 km and 10,000 m of positive height gain.
The week comprises seven races of different lengths, each offering a unique variation around Mont Blanc, from shorter routes to full loops of the massif.
- UTMB® (Ultra-Trail du Mont-Blanc): 170 km / +10,000 m
- CCC® (Courmayeur–Champex–Chamonix): 100 km / +6,100 m
- TDS® (Sur les Traces des Ducs de Savoie): 145 km / +9,100 m
- OCC (Orsières–Champex–Chamonix): 55 km / +3,500 m
- PTL® (La Petite Trotte à Léon): about 300 km / +25,000 m – team challenge
- MCC (Martigny–Combe–Chamonix): 40 km / +2,300 m – open to volunteers and local runners
- YCC (Youth Chamonix Courmayeur): 15 km / +1,200 m – for young athletes
About UTMB®
The UTMB® (Ultra-Trail du Mont-Blanc) was first held in 2003, with additional races added from 2006 onwards. The route largely follows the classic Tour du Mont Blanc hiking trail, forming a loop around Mont Blanc and crossing France, Italy, and Switzerland.
The key difference is that while most hikers complete the Tour du Mont Blanc in 7–10 days, runners of the main UTMB® race cover the same distance in around 30–45 hours. The elite runners usually finish in just over 20 hours.
Since the inaugural race in 2003, both the number of entrants and its global popularity have grown exponentially. Just three years later, the entry cap of 2,500 runners was exceeded, leading to the creation of the CCC® (Courmayeur–Champex–Chamonix) to give more athletes the chance to take part.
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Since 2007, runners have had to gain qualifying points before being able to enter the race, and almost every year since, the criteria have been refined to select participants based on both ability and experience. Today, athletes earn UTMB Index scores and collect Running Stones at official UTMB® World Series events, which they can then use to enter the draw for a place in the Mont-Blanc finals.
Because the race is so oversubscribed, there’s also an element of chance: even qualified runners must go through a lottery system that randomly allocates places from among those who meet the entry criteria.
From the pros to the first-timers, every competitor is required to carry a comprehensive list of mandatory equipment to ensure safety across all conditions. This includes waterproof clothing, warm layers, a headlamp with spare batteries, phone, food and hydration, and an emergency survival blanket. Checks can take place before or during the race, and missing items may lead to time penalties or disqualification.
A quick history of UTMB®
2003: The race is run through rain, cold and hailstones, with 711 trail-runners on the start line from 19 different countries.
2004: Local boy Vincent Delebarre wins the UTMB®.
2006: The CCC® is run for the first time, and is won by the female runner Corinne Favre.
2008: The youngest entrant in that year’s race, Kilian Jornet, wins his first UTMB® at just 20 years of age.
2009: In searing temperatures of 28-30 °C, Kilian Jornet takes the top podium for the second time. Another new race, the TDS®, is also introduced.
2010: The first attempt at the race is called off after rain causing rock-slides. A second start the next day crowns Brits the champions — Jez Bragg and Lizzy Hawker (who won her first UTMB® in 2005 and holds the record for highest number of wins – 6).
2012: Another year of hellish weather conditions makes it impossible to race in Italy, so the race is shortened and redirected in France.
2014: The OCC is run for the first time.
2015: A sunny and hot week for all the races makes it especially challenging, especially for those running the team PTL® event. Only 17 out of 115 registered teams make it to the finish line within the time limit.
2018: Financial prizes are offered for the first time, with men and women winning equal prize money for taking top positions in the four main individual competitions: UTMB®, TDS®, CCC®, OCC.
2020: The 2020 edition is cancelled due to the coronavirus pandemic.
2023: The event becomes part of the newly branded UTMB® World Series Finals, signaling a next evolution in the series.
2025: The race continues to attract elite performances, new records and global attention, reinforcing its status as the pinnacle of mountain ultrarunning.
Innovation at UTMB®
The UTMB® prides itself on being at the forefront of innovation in trail running — from sustainability to technology and community engagement.
Environment: All runners must carry a personal cup and waste pouches to reduce single-use materials. Environmental ambassadors work before, during, and after the races to minimise the event’s impact on the Mont Blanc region. The organisation also promotes a shared transport system for runners, volunteers, friends and family to reduce traffic in the valley.
Health: The UTMB® has developed a strict health policy, including medical questionnaires and anti-doping controls, and it participates in international research projects on endurance sport and altitude performance.
Race coverage: Each runner’s location is tracked live via GPS chips integrated into their race bibs, allowing spectators to follow progress in real time. SMS updates and push notifications alert supporters as runners pass checkpoints, and live race coverage is broadcast globally.
Communication: The UTMB® offers live streaming and commentary in several languages — including French, English and Spanish — along with on-site interviews, social media updates, and dedicated race apps.
Trail runners of the future: The event also invests in inspiring the next generation. Programmes such as the Mini-UTMB®, Y Run, and YCC (Youth Chamonix Courmayeur) give children, teens, and young adults the chance to experience trail running in a safe and inclusive environment.
Watch ®UTMB Chamonix centre
If you’re in Chamonix to support a friend or family member, you’ll likely find yourself dashing around the course to cheer them on and offer encouragement.
Even if you’re not directly involved, it’s impossible to miss the electric atmosphere that fills the town during UTMB® week. The best place to experience it is near the large UTMB® arch on Place du Triangle de l’Amitié, right in front of the Chamonix town hall. Both the PTL® and UTMB® races start from this central square, and every race throughout the week finishes here.
Settle in at one of the nearby cafés or bars and watch as runners dig deep to cross the finish line. The energy is contagious — be sure to join in the clapping and cheering to help them through those final, emotional metres!
If you’re out exploring the mountains during UTMB® week, you’re also likely to spot runners on the trails — particularly around Le Tour, Vallorcine, Flégère, and Les Houches — as they make their way through some of the most iconic sections of the course.
This year, we also introduced our very own Chamonix All Year Cheer Zone at Lake Gaillands, a scenic and easy-to-reach spot just outside town. It quickly became one of the most spirited places to support runners as they passed by, with music, refreshments, and plenty of encouragement from locals and visitors alike.
Why we love UTMB®
Here at Chamonix All Year, we absolutely love UTMB® week. Chamonix is always lively in summer, but during the last week of August the town truly bursts at the seams. It’s one of our busiest and most exciting weeks of the year, with guests arriving from all over the world — many with friends and family here to cheer them on.
At any hour of the day or night, you’ll find the barriers along the finish line packed with people clapping, cheering, and celebrating every runner’s incredible achievement as they cross under the iconic UTMB® arch in the centre of town. The energy, emotion, and community spirit make it one of the most unforgettable times to be in Chamonix.
If you’ve secured a place to run this year, make sure you book your UTMB® Chamonix accommodation early — our properties fill up fast and availability is limited during this incredible week. Whether you’re racing, supporting, or simply here to soak up the atmosphere, we have a wide range of chalets and apartments to suit every group and budget.
Head to Chamonix All Year to find the perfect base for your UTMB® adventure and experience one of the most inspiring events of the year right here in Chamonix.
