100 mile ultra runs
A 100-mile ultra is one of the hardest challenges in endurance running. These iconic events test physical strength, mental resilience and race strategy over extreme distances. Use the filters to explore 100-mile ultras across the UK, Europe and beyond. Read more
Covering 100 miles or more, these ultra events demand months of preparation and careful planning. Courses often include mountain terrain, remote trails, night running and strict cut-off times.
Many 100-mile ultras are steeped in tradition and attract experienced runners from around the world. Support crews, navigation skills and detailed nutrition plans are often essential.
If you’re building toward this distance, start by exploring 50K ultra runs or 100K ultra runs to gain experience before stepping up to the full 100 miles.
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 view100 mile ultra runs 2026–2027
Discover 100 mile ultras across the UK and beyond and get ready for your next start line.
- Fri 24 Apr 2026
- £100-£120
Thames Ring Series | TR100
Tackle the new addition to the Thames Ring Series — a 100-mile ultra along rivers and canals, combining stunning scenery, grit, and determination in one unforgettable endurance adventure.
- 100 miles trail running
- Sat 23 May 2026
- £163-£165
Farmmageddon | 100 Miles
Can you survive Farmmageddon? Held over 32-hours, runners will cover the fantastic 5.3K loop through the lovely grounds of Hyde Hall Farm and receive a t-shirt, buckle and medal to prove it!
- 100 miles trail running
- Sat 11 - Sun 12 Jul 2026
- £129.99-£319.99
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
- Sat 25 Jul 2026
- £330
Rat Race 100 Ultramarathon
The 100-mile ultra for people who don't do 100-mile ultramarathons. Walk or run from Edinburgh Castle to Glamis within 48 hours, fully supported.
- 100 miles trail running + 4853 ft ascent
- Fri 18 - Sun 20 Sep 2026
- £160-£220
Skyline Scotland | Skyline Scotland 100M
Climb from Glen Nevis to Sgurr an Iubhair, traverse remote Corrour and Loch Ossian, then race rugged trails, forests and singletrack to a spectacular Nevis Range finish on this mountain adventure.
- 100 miles fell running + 4600 m ascent
- Sat 12 - Sun 13 Sep 2026
- £164
Robin Hood 100
This is a fully marked ultra on nice underfoot, runnable and scenic trails. The route heads into Sherwood Forest to take in Robin Hood’s homeland before returning back to South Wheatley.
- 100 miles road running
- Fri 18 Sep 2026
- £99
Peak District Challenge | 100 Miles Ultra
Set off 9pm Friday; get back by 9pm Saturday. Navigate 100 miles through the night via set checkpoints over hilly and challenging terrain and maintain 7kph throughout.
- 100 miles trail running + 4800 m ascent
- Thu 26 Nov - Sat 5 Dec 2026
- €2,600-€3,000
La Transtica | Extreme Race
The unique crossing of Costa Rica in five stages.
- 122 miles trail running + 9300 m ascent
100 mile ultra marathon blog
Guides, tips and advice on running a 100 mile ultra marathon.
- 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!
100 mile ultra marathon FAQs
Answers to the most common questions about running a 100 mile ultra marathon.
A 100-mile ultra covers 160 kilometres or more, making it one of the longest standard ultra distances.
Training often takes 6–12 months and usually includes experience at shorter ultra distances first.
Many events allow support crews at designated checkpoints, though rules vary by race.
100 mile ultra runs near you
Select your location for 100 mile ultra marathons in your area.