CCC and OCC Race Guide: UTMB's Sister Races Explained

CCC and OCC race guide: 101 km versus 60 km, elevation and cutoffs compared, UTMB index requirements, and training outlines for each Mont-Blanc distance.

Everyone talks about UTMB, and most people should be running CCC or OCC instead. The two sister races share the same Mont-Blanc terrain, the same late August race week in Chamonix, and the same finish line under the same crowds, at distances that a well-trained amateur can actually complete without a two year specific build. CCC covers 101 km with 6,050 m of climbing. OCC covers 60 km with roughly 3,500 m. This guide compares both, covers the entry route, and helps you pick the one that matches where you actually are.

CCC: Courmayeur to Champex to Chamonix

The numbers for 2026: 101 km, around 6,050 m of positive elevation, a 26 hour 30 minute limit, starting from Courmayeur in Italy at 09:00 on the Friday of race week (UTMB Mont-Blanc, 2026).

CCC follows the final section of the UTMB loop, which means it delivers the most famous terrain of the whole course (Salomon, 2026). The route crosses from Italy into Switzerland and then France, taking in Tête de la Tronche, Grand Col Ferret at 2,537 m, Champex-Lac, Bovine, Trient, and the final climb to Tête aux Vents before the descent into Chamonix.

What makes it hard:

  • A 1,400 m climb inside the first 15 km, taken from a standing start with 2,000 runners
  • Grand Col Ferret arrives early enough that people go too hard on it
  • The second half contains three substantial climbs when your legs are already gone
  • The 09:00 start means most runners cover the last section through the night

Who it suits: runners with a 50 km to 80 km trail background and at least one season of consistent vertical training. Realistically, expect 16 to 24 hours for a mid-pack finish.

OCC: Orsières to Champex to Chamonix

The numbers for 2026: 60 km, roughly 3,500 m of climbing, a 14 hour 30 minute limit, starting from Orsières in Switzerland at 08:15 on the Thursday (UTMB Mont-Blanc, 2026). The 2026 edition reworks the upper section between Col de Balme and Col des Posettes, with a new high point at 2,321 m.

Shorter does not mean easy. OCC packs a genuinely mountainous profile into 60 km, and because the field is faster the atmosphere is closer to a long mountain race than a slow ultra.

What makes it hard:

  • The climb out of Orsières to Champex starts immediately
  • Bovine is steep, technical, and comes at the point where the early pace catches people
  • The cutoff of 14:30 is not generous for the vertical involved
  • The final descent into Chamonix is long and quad-destroying

Who it suits: runners stepping up from marathon or 50 km trail distances, and faster runners wanting a hard single-day mountain race. Expect 8 to 13 hours mid-pack.

Choosing between CCC and OCC

Consideration OCC CCC
Distance 60 km 101 km
Climbing around 3,500 m around 6,050 m
Time limit 14h30 26h30
Night running usually none for most finishers yes, for nearly everyone
Longest training run needed 5 to 6 hours 7 to 9 hours, back to back
Weekly vertical in peak block 1,500 to 2,500 m 2,500 to 4,000 m

The honest test is night running and sleep deprivation. If you have never run through the dark for six hours, OCC is the better first Mont-Blanc race. It is not a consolation prize. Plenty of strong runners choose it deliberately.

Our guide on trail race categories covers how these distances sit against each other more broadly.

Getting a place

Both races use the same system as UTMB: a UTMB Index at the correct distance category, at least one active Running Stone, and a weighted lottery draw.

  • OCC requires an index from a 20K category race
  • CCC requires an index from a 50K category race

That difference matters when planning your qualifying year, because a single well-chosen race can set you up for one and not the other. Our UTMB lottery and Running Stones guide explains the mechanics in full.

Pre-registration opens in late autumn or early winter for the following August, with the draw over winter. Odds for CCC and OCC are better than for UTMB itself, though both remain oversubscribed.

Training for a Mont-Blanc sister race

The demands are the same in kind, different in degree: sustained climbing, long technical descending, and altitude between 1,000 and 2,600 m.

CCC, 20 week outline:

  • Weeks 1 to 6: base, weekly vertical building to 1,800 m, long runs to 4 hours
  • Weeks 7 to 13: specific, back-to-back weekends, weekly vertical 2,500 to 4,000 m, one night run every three weeks
  • Weeks 14 to 17: peak, longest efforts 7 to 9 hours with 2,000 m plus, full kit rehearsal
  • Weeks 18 to 20: taper

OCC, 16 week outline:

  • Weeks 1 to 5: base, weekly vertical to 1,200 m
  • Weeks 6 to 11: specific, weekly vertical 1,500 to 2,500 m, sustained climbing intervals
  • Weeks 12 to 14: peak, longest runs 5 to 6 hours with 1,500 m plus
  • Weeks 15 to 16: taper

Descending is the most under-trained element for both. The drop into Chamonix arrives after everything else and it is where finishing times fall apart. Our downhill technique guide covers the mechanics.

Run the Race Predictor against the actual profile before you set a target, since Mont-Blanc gradients make road-based estimates useless. Then use the Race Readiness check to see whether your vertical is tracking toward what the race needs.

Race week logistics

  • Mandatory kit is enforced by spot checks and is substantial: taped waterproof jacket, second warm layer, long trousers or leggings, gloves, hat, headlamp with spare, phone, cup, survival blanket, whistle, and food reserve
  • Transport to the start is by organised bus from Chamonix, early, and you must book it
  • Accommodation in Chamonix during race week is expensive and books out roughly a year ahead. Look at Argentière, Les Houches, or Servoz
  • Cup rule: no disposable cups on course. Carry your own
  • Weather: anything from 30 C in the valley to snow on the cols, in the same race

Key takeaways

  • CCC is 101 km with 6,050 m of climbing and a 26h30 limit, OCC is 60 km with 3,500 m and 14h30
  • OCC needs a 20K category index, CCC needs a 50K category index, and both need a Running Stone
  • Night running experience is the honest dividing line between the two
  • Both finish in Chamonix under the same crowds as UTMB
  • The final descent decides more finishing times than any of the climbs

Where to go from here

Pick the race that matches the training you can genuinely commit to over the next year, then choose your qualifying race to match the index category it needs. Runners who enter CCC because it sounds more serious and then arrive with OCC training make up a large share of the withdrawal list at Champex.

Trailia builds the block around the specific elevation profile of whichever race you choose, so weekly vertical and long run structure track the demands rather than a generic template.

Citations

  • UTMB Mont-Blanc (2026). CCC race page, course profile and regulations.
  • UTMB Mont-Blanc (2026). OCC race page, course profile and regulations.
  • iRunFar (2026). UTMB World Series Finals race week coverage.
  • Salomon (2026). CCC Courmayeur to Champex to Chamonix race overview.

Frequently Asked Questions

What is the difference between CCC and OCC?

CCC covers 101 km with around 6,050 m of climbing and a 26 hour 30 minute limit, starting from Courmayeur in Italy. OCC covers 60 km with roughly 3,500 m of climbing and a 14 hour 30 minute limit, starting from Orsières in Switzerland. Both finish in Chamonix during the same late August race week.

Is OCC easier than CCC?

It is shorter, but it packs a genuinely mountainous profile into 60 km and the 14 hour 30 minute cutoff is not generous for the vertical involved. The field is also faster, so the atmosphere resembles a hard single-day mountain race rather than a slow ultra. The clearest difference is that most OCC finishers avoid running through the night.

Which UTMB index do I need for CCC and OCC?

OCC requires an index from a 20K category race, while CCC requires an index from a 50K category race. This difference matters when planning your qualifying year, since one well-chosen race can set you up for one and not the other. You also need at least one active Running Stone for either.

Should I run OCC or CCC first?

The honest test is night running. If you have never run through the dark for six hours, OCC is the better first Mont-Blanc race, and plenty of strong runners choose it deliberately rather than as a consolation. CCC suits runners with a 50 km to 80 km background and a season of consistent vertical training behind them.

How long does it take to finish CCC?

Mid-pack finishers typically take 16 to 24 hours against a 26 hour 30 minute cutoff. The 09:00 Friday start means nearly everyone covers the final section in darkness. The three substantial climbs in the second half are where most time is lost.

What mandatory kit do CCC and OCC require?

The list is substantial and enforced by spot checks: a taped waterproof jacket, second warm layer, long trousers or leggings, gloves, hat, headlamp with spare batteries, phone, cup, survival blanket, whistle, and a food reserve. There are no disposable cups on course, so you must carry your own. Check the current year's list before packing.

How much vertical should I train for CCC?

Aim for weekly vertical of 2,500 to 4,000 metres during the specific phase, with back-to-back long run weekends and longest efforts of 7 to 9 hours including 2,000 metres or more. For OCC, 1,500 to 2,500 metres weekly and longest runs of 5 to 6 hours is a reasonable target. Descending is the most under-trained element for both races.

Are CCC and OCC easier to get into than UTMB?

Odds are better than for the flagship UTMB, but both remain oversubscribed and run through the same weighted lottery. You still need a valid index at the right distance category and at least one active Running Stone. Pre-registration opens in late autumn or early winter for the following August.

Where do I stay for CCC or OCC race week?

Chamonix accommodation during UTMB week is expensive and books out roughly a year ahead, so look at Argentière, Les Houches, or Servoz as alternatives. Transport to both start lines is by organised bus from Chamonix, departing early, and you must book it in advance. Plan for very little sleep the night before either race.

What weather should I expect on the Mont-Blanc courses?

Anything from 30 C in the valley to snow on the high cols, sometimes within the same race. That range is exactly why the mandatory kit list is as long as it is. Both courses spend hours between 1,000 and 2,600 metres, where conditions change quickly.

Tools for this race