The world's most prestigious mountain ultra series. Six race distances from 15km to 171km, circumnavigating Mont Blanc through France, Italy and Switzerland. The pinnacle of trail running.
Brennan has competed at UTMB World Series events including the OCC. Both Brennan and Kat actively compete in the UTMB World Series, giving them direct experience of qualification, preparation and race execution at this level.
171km · 10,000m+ · The full circumnavigation of Mont Blanc — France, Italy, Switzerland. The world's most famous trail race.
Finals Race101km · 6,050m+ · Courmayeur to Chamonix via Champex. The 'little sister' of the UTMB.
Finals Race60km · 3,500m+ · Orsières to Chamonix. Mid-distance UTMB World Series Final. 2026 includes a new high point at 2,321m.
Finals Race153km · 9,000m+ · Sur les Traces des Ducs de Savoie. The wildest and most technical route of the week.
4 Stones Req.40km · 2,350m+ · Martigny-Combe to Chamonix. Open to volunteers, partners and locals.
Non-Finals15km · 1,200m+ · Trail Experience Courmayeur. Dynamic, fast, explosive short mountain race.
Non-FinalsThe HOKA UTMB Mont-Blanc is the most famous trail running event in the world — 10,000+ runners from 100+ countries converging on Chamonix each August. It is the UTMB World Series Finals for the UTMB, CCC and OCC distances, making it the pinnacle of the global trail running season.
The main UTMB race — 171km and 10,000m of elevation circumnavigating Mont Blanc through three countries — is considered the greatest ultra marathon challenge in the world. Entry is by lottery, requiring Running Stones earned through UTMB World Series qualifier events.
Compete in UTMB World Series events to earn Running Stones for lottery entry. UTS, Arc of Attrition and Lakeland 100/50 all contribute stones.
Training at altitude and on technical Alpine terrain is ideal for UTMB preparation. If you can't get to the Alps, UTS and Scottish mountain events are excellent substitutes.
The UTMB typically takes most runners 25-45 hours — multiple nights of running. Practice long overnight efforts and understand how your body responds to severe sleep deprivation.
Fuelling for 40+ hours of effort requires a very specific strategy. Train your gut systematically, know what you can eat under maximum fatigue, and have backup options at each major aid station.
UTMB week in Chamonix is the largest mountain running event in the world. Over five days in late August, multiple races start and finish in Chamonix with a combined entry of over 10,000 runners. The three main races — OCC, CCC and UTMB — differ dramatically in distance, difficulty and qualification requirements.
The OCC is the entry point to UTMB week for most runners. Starting in Orsières in Switzerland and finishing in Chamonix, it covers 56km with 3,500m of ascent. Cutoff is approximately 23 hours, and the qualification index threshold is the lowest of the three races. This is still a serious mountain race in genuine Alpine terrain — not a beginner event, but achievable for well-prepared fell and mountain trail runners.
The CCC (Courmayeur–Champex–Chamonix) is a genuine test of ultra mountain running. Starting in Courmayeur in Italy, it crosses into Switzerland and finishes in Chamonix after 101km and 6,100m of ascent. Cutoff is approximately 40 hours. The qualification index requirement is substantially higher than OCC. This is the right race for experienced ultra runners with Alpine ambitions.
The Ultra Trail du Mont Blanc is one of the world's defining endurance events: 171km around the Mont Blanc massif crossing France, Italy and Switzerland with 10,000m of ascent. Cutoff is 46 hours and the qualification index requirement is the highest of any race in the UTMB series. This is a race for elite ultra athletes with multiple 100-mile finishes and specific high-mountain experience.
Most runners should begin with OCC and progress to CCC before considering UTMB. The jump from CCC to UTMB is significant — not just in distance but in the mountain demands, the mental commitment and the physiological toll. Index points force this progression to some degree, but let experience rather than ambition drive the decision.
The UTMB Index system replaced the previous stones-based qualification system. Each runner accumulates a personal running score through qualifying races, and each UTMB race requires a minimum score. Scores decay over time — points from races more than three years old count less. Always check the official UTMB website for current requirements as thresholds change annually.
OCC typically requires around 200 UTMB index points; CCC requires approximately 450; UTMB itself requires approximately 750. These are approximate and change year to year — always verify on the official UTMB website before planning your qualification strategy. The ballot system also applies, so qualifying does not guarantee a place.
The UK offers several high-value UTMB index races. Lakeland 100 and Lakeland 50 are among the most significant. UTS 100 provides strong index points and excellent Alpine preparation. Dragon's Back Race is one of the most prestigious UK qualifiers. Combining two or three of these over two to three years builds a strong qualification profile.
UTMB index points from races within the last year count in full; older points decay. This encourages active racing rather than resting on historic results. Plan your qualification over two to three seasons: build index progressively, race consistently, and ensure your peak qualifying scores fall in the two years before your target entry.
Reaching the minimum index threshold does not guarantee a place at UTMB, CCC or OCC. All three main races are significantly oversubscribed. Runners above the threshold enter a ballot. Higher index scores increase ballot odds to some extent. Plan for the possibility of ballot failure and have an alternative race in your season plan.
UTMB week is as much an event as a race. The Chamonix valley fills with runners, crews, spectators and mountain running culture from across the world. Understanding the logistics of race week is as important as the physical preparation.
Registration takes place at the Chamonix sports hall during race week. Kit check is thorough and no exceptions are made. Mandatory kit includes emergency rations, first aid kit, phone with race app, poles (for most distances), waterproof jacket and trousers, thermal layer, and emergency space blanket. Arrive with everything or risk disqualification before you start.
The UTMB start in Chamonix's Place du Triangle de l'Amitié is unlike any other race start in the world. Thousands of runners, music, and an electric atmosphere. But it's also where runners go out catastrophically too fast. The crowd energy, the emotion and the night start combine to destroy pacing discipline. Start conservatively. You have 170+ kilometres ahead of you.
The UTMB organisation maintains mountain rescue capability along the entire route. But this is not an excuse for under-preparation. The mountains are genuine Alpine terrain and serious weather events occur during the race most years. Know how to use your mandatory kit and understand the mountain rescue protocol if you need to trigger it.
Race week in late August can be anything from warm and clear to severe electrical storms with snow above 2,500m. 2012, 2019, and other editions have seen significant weather events. Always pack for cold above 2,500m regardless of the forecast. A single weather window can close faster in the Alps than anywhere else in Europe.
The Alps demand preparation that goes beyond standard ultra training. Altitude, technical terrain, extreme elevation gain per kilometre, and the sheer duration of the event all require specific preparation that most UK runners don't build into their training plans.
Chamonix sits at 1,035m and the UTMB route reaches 2,537m at the Grand Col Ferret. While this isn't Himalayan altitude, UK runners based at sea level often feel the effects. A training camp at altitude — Chamonix itself, the Alps, or even the Pyrenees — in the months before the race provides valuable adaptation and course familiarity.
The descents in UTMB races are long, steep and fast. Quad-destroying by mile 80 for UTMB, quad-destroying by mile 50 for CCC. Build specific quad strength with weighted step-downs, single-leg press work, and long technical descending runs. Arrive at the start with the strongest legs you've ever had.
Poles are mandatory for UTMB and CCC, and strongly recommended for OCC. If you've never raced with poles, start using them in training immediately. The climbing technique with poles is specific — double-pole plant on steep ascent, stow quickly for technical sections. Build this into your training months before race day.
Aim for at least two years of consistent ultra experience before CCC, and three or more before UTMB. A recce of key sections — Grand Col Ferret, Col de la Seigne, the final approach to Chamonix — builds confidence and tactical knowledge that cannot be obtained from watching YouTube videos or reading route descriptions.
Brennan's Coach Note: I've coached runners through all three main UTMB distances. The one thing that distinguishes those who finish comfortably from those who suffer is specificity of preparation. Not just mileage — specific mountain training, specific quad strength, specific Alpine exposure. Start that preparation at least 6 months out. And enter OCC before you dream about UTMB.
We build bespoke training plans and coaching packages for this race. Get in touch to discuss your preparation.
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