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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100K ultra runs in 2025
Featured events are listed below - select a month/region or the map view to see all events.
- Sat 26 Apr
- £84.50
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
- Sat 3 - Sun 4 May
- £39-£199
Isle of Wight Ultra Challenge
Great challenges need great settings, and up to 2,000 adventurers will take on the Isle of Wight stunning coastal path – all out to push themselves further this year!
- Trail run 3
- 50K ultra run 3
- 100K ultra run 2
- Ultra run
- Sat 3 May
- £75-£77
ATW Mallory Race Circuit 100K
Get ready for the challenge of a lifetime at the Mallory Park 100K race! A unique and thrilling chance to race on the same legendary motor racing circuit that once hosted a Formula 1 event!
- 100 km multi terrain running
- Sat 17 - Sun 18 May
- £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 24 - Sun 25 May
- £89-£199
London 2 Brighton Ultra Challenge
Walk, jog or run the capital-to-coast route with 2,000 other adventurers over a range of distance options available and superb support all the way, for all abilities and experience levels.
- Trail run 3
- Ultra run 2
- Marathon
- 100K ultra run 2
- Sat 7 - Sun 8 Jun
- £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 21 - Sun 22 Jun
- £39-£199
Cotswold Way Ultra Challenge
Challenge yourself in the rolling hills of the Cotswolds featuring the Cotswold Way itself, villages, footpaths and trails with fabulous views on route plus full support and hospitality.
- Trail run 2
- Ultra run 4
- 100K ultra run
- 10K run
- Sat 21 Jun
- £170-£180
Race to the King | 100K
Take on the full 100K Race to the King ultra marathon challenge in one go. Fully supported through day and night on a route combining castles and coastal scenery.
- 100 km trail running + 4619 ft ascent
- Sat 28 - Sun 29 Jun
- £39-£199
Peak District Ultra Challenge
From the idyllic basecamp hub in Bakewell, charity challengers will head into the fabulous Peak District National Park on a route from 10 miles right up to the full 100km with full support!
- Ultra run 3
- 100K ultra run 2
- Trail run 2
- Sat 12 - Sun 13 Jul
- £85-£270
Race to the Stones
Conquer Britain's oldest trail, the ancient Ridgeway, at the UK's biggest ultramarathon as you race towards the 5000-year-old Avebury Standing Stones. Back for the 12th Year Running!
- 50K ultra run 2
- 100K ultra run 3
- Sat 12 - Sun 13 Jul
- £121.99-£251.99
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
- Sat 19 - Sun 20 Jul
- £39-£199
Gower Peninsula Ultra Challenge
A new Ultra Challenge for this year, set on the stunning Gower Peninsula – the UK’s first Area of Outstanding Natural Beauty and famous for its golden beaches.
- 100K ultra run 2
- Ultra run
- 50K ultra run 2
- Marathon
- Multi-terrain run
- + 1 more race
- Sat 6 - Sun 7 Sep
- £89-£199
South Coast Ultra Challenge
The South Downs National Park is a superb backdrop for a real challenge featuring Beachy Head, the Seven Sisters and the South Downs Way with a choice of distances from 25km right up to 100km!
- 100K ultra run 2
- Ultra run 2
- Trail run
- Fri 12 - Sun 14 Sep
- £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 7 Jun
- £109
Ultra Scotland 50
Take on 50 historic miles across the beautiful Southern Upland Way - one of the greatest trails in the UK. Ultrarunners will tackle several ascents, pass through forests, valleys and by lochs.
- 56 miles trail running + 2447 m ascent
- Sat 23 Aug
- £90-£108
Run the Borders | Full 109K
Visiting the heartland of the Scottish Borders, runners and walkers will take to the Borders Abbey Way to complete the full waymarked loop as individuals, teams or a relay of four.
- 109 km trail running
100K ultra runs near you
Select your location for 100K ultra marathons in your area.