100K ultra runs
A 100K ultra pushes runners into full ultra-distance territory. These demanding events test endurance, pacing and mental resilience across long hours on the trail. Use the filters to find 100K ultras by date, location or terrain. Read more
A 100K ultra run covers around 62 miles and is a major step up from shorter ultra distances. These events often include significant elevation, technical terrain and long cut-off times, requiring careful preparation and race strategy.
Many 100K ultras are trail-based and take runners through remote landscapes, mountain paths or long point-to-point routes. Aid stations, navigation and mandatory kit play a bigger role at this distance.
If you’re working up to something even bigger, explore our 100-mile ultra events — the ultimate endurance challenge in ultra running.
Want to read more? Read the guides, tips and advice from our blog.
Got questions? Read our FAQs for answers.
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Map view100K ultra runs 2026–2027
Discover 100K ultras across the UK and beyond and get ready for your next start line.
- Sat 25 Apr 2026
- £90.50
North Wales 100K
This event gives participants the opportunity to take in a runnable, beautiful route which follows the North Walian coastline between Prestatyn and Bangor.
- 100 km trail running + 8000 ft ascent
- Sat 20 - Sun 21 Jun 2026
- £49-£199
North Yorks Ultra Challenge
Set to be one of the greatest Ultra Challenges – basecamp is in Scarborough – famous for its Fair, and a popular seaside spa since the 17th century.
- 100K ultra run 2
- 50K ultra run 2
- Trail run
- 10 miler
- Sat 20 Jun 2026
- £175
Race to the King | 100K Non-Stop
The full circuit takes in both the Coastal and Castle loops for a magnificent tour of the stunning South Downs. Steeped in history and uniquely varied, the 100K offers a course truly fit for royalty.
- 100 km trail running + 1510 m ascent
- Sat 11 - Sun 12 Jul 2026
- £90-£275
Race to the Stones
Conquer Britain's oldest trail, the ancient Ridgeway, as you race towards the 5000-year-old Avebury Standing Stones.
- 50K ultra run 2
- 100K ultra run 3
- Sat 19 - Sun 20 Sep 2026
- £140-£200
Skyline Scotland | Skyline Scotland 100K
A runnable 100km with a Scottish Highland journey at the heart of the race experience with an exciting midnight mass start.
- 106 km trail running + 6350 m ascent
- Sun 22 Mar 2026
- £90-£120
Canalathon-Ultra Running Festival | 100K
Enter this deliciously scenic romp over distances of 100km, 50km, Half Marathon or 10km. Go big or stay home!
- 100 km road running + 377 m ascent
- Sun 3 May 2026
- £77
Tempo Trail Races | 100K Ultra
Tempo Trail Races 2026 are open for entry!!!
- 100 km trail running + 6682 ft ascent
- Sat 9 May 2026
- £118-£120
Chiltern Hills 100K
A 100K ultra marathon along the best and most loved trails within the Chiltern Hills.
- 100 km trail running
- Sat 16 - Sun 17 May 2026
- £39-£199
Jurassic Coast Ultra Challenge
Walk, jog or run along the spectacular UNESCO World Heritage coastline from Corfe Castle past Lulworth Cove and Durdle Door, with full support, welcoming base camp and finish line celebration!
- Trail run 2
- 50K ultra run 2
- 100K ultra run 2
- Marathon
- Ultra run
- + 1 more race
- Sat 6 - Sun 7 Jun 2026
- £39-£199
Lake District Ultra Challenge
Take on England’s finest countryside at your own pace with stunning views all the way, featuring the Garburn Pass, historic Ambleside, a halfway point by Lake Windermere, forests and nature reserves.
- Trail run 2
- 50K ultra run 2
- 100K ultra run 2
- Marathon
- Sat 20 Jun 2026
- £20-£100
Two Rose Ultra | Two Roses Ultra - 100K
An ultramarathon with a difference, The usual ultra set-up with a bit extra thrown in: this unique event offers you a choice between two 50km loops or the full 100km.
- 100 km multi terrain running + 5175 ft ascent
- Fri 3 - Sat 4 Jul 2026
- £103-£105
The Full Essex Way Ultra
Starting at Epping tube station in London and finishing at the high lighthouse in the historic port of Harwich, the ultra covers the full 82 miles of the beautiful Essex Way Trail.
- 82 miles trail running + 3469 ft ascent
- Sat 11 - Sun 12 Jul 2026
- £129.99-£374.99
Black Diamond Yr Wyddfa Snowdon24
Yr Wyddfa (Snowdon) is the highest mountain in England and Wales. Your challenge is to ascend and descend as many times as possible in 24 hours - solo or as a relay team.
- 24 hrs trail running + 3182 ft ascent
- Fri 11 - Sun 13 Sep 2026
- £39-£199
Thames Path Ultra Challenge
England’s greatest river provides a fantastic backdrop for an unforgettable 'festival' challenge weekend, with distances from 10km right up to 100km there’s a Thames Challenge for everyone!
- 100K ultra run 2
- 50K ultra run 2
- Trail run 4
- Ultra run
- 10K run
- + 4 more races
- Fri 18 Sep 2026
- £86
Peak District Challenge | Gold Ultra 100K
A hilly and challenging route showcasing the best of the Peak District for those who can maintain 4kph over 24 hours. Night navigation experience is essential.
- 100 km trail running + 3300 m ascent
100K ultra marathon blog
Guides, tips and advice on running a 100K ultra.
- 10 mins read
Race 101: the 13 Valleys Ultra
Introducing the 13 Valleys Ultra plus the event's shorter distance options, helping you to push your limits and get involved!
- 8 mins read
10 best ultra marathons in the UK
Take on an epic endurance challenge with one of the most popular ultra runs in the UK, from traditional fell runs to the UTMB World Series!
100K ultra marathon FAQs
Answers to the most common questions about running a 100K ultra marathon.
A 100K ultra is approximately 62 miles, often taking runners many hours to complete.
Most 100K events recommend prior marathon or ultra experience due to distance, terrain and cut-off times.
Completion times vary widely due to the different terrain - some of the easier events can be completed in 12-15 hours, some of the mountainous events can take 1-2 days.
100K ultra runs near you
Select your location for 100K ultra marathons in your area.