100K ultra runs in the UK
The middle of the common ultra distances at just over 60 miles, 100K ultra marathons are a big step up from the marathon. Despite this, distance is not always the key challenge with ultra runs - the total ascent gives a much better indication of how hard it will be. Select your location to find 100K ultra runs in your area or scroll down to browse events coming up.
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Map view100K ultra runs in 2025/2026
Featured events are listed below - select a month/region or the map view to see all events.
- 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 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 - 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
- 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
- Sat 11 - Sun 12 Jul 2026
- £121.99-£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
100K ultra runs near you
Select your location for 100K ultra marathons in your area.