50K Ultra Marathons
Fully marked, well-supported 50K trail ultras in the Chiltern Hills, North Chilterns and along the Suffolk coast. Ideal for a first ultra.
Your first ultra starts here
The 50K is where most runners start their ultra running journey. It's only 8km further than a marathon, but on trails it feels completely different. You'll spend 4 to 9 hours on your feet, often walking the climbs, eating at checkpoints and running the rest.
We put on three 50K trail ultras in the Chiltern Hills and one on the Suffolk coast, plus the 60K Ridgeway Chase for runners who want something a little longer. Over 1,000 runners finished one of our 50Ks in the last year.
What to expect at a Runaway Racing 50K
- A 9-hour time limit at every 50K, so walking the hills is not just allowed, it's expected.
- Fully marked routes with our orange arrows and ribbons, so you can focus on running, not navigating.
- Well-stocked checkpoints with water, Coke, Precision Fuel & Hydration electrolyte drink, gels and plenty of snacks.
- UTMB Index on every race, and live results on the day.
- A high finish rate. At our latest 50Ks, between 96% and 99% of starters reached the finish.
Hilly 50Ks in the Chilterns
The Chiltern Ridge Classic 50K runs point to point from Berkhamsted Castle to Wendover, passing Ashridge, Ivinghoe Beacon, Coombe Hill and Whiteleaf, with almost 1,000m of climbing. Its autumn sister race, the Chiltern Ridge Winter 50K, is a single loop from Berkhamsted.
For rolling ridgelines, the North Chilterns 50K starts at the Putteridge Bury Estate near Luton and takes in Warden Hill and the Barton and Pegsdon Hills, with around 800m of climbing.
Flat, coastal, or a step beyond
The Suffolk Coastal Path 50K is one of the flattest ultras in the UK, with only around 120m of ascent. It runs point to point from Lowestoft to Aldeburgh via Southwold, Dunwich and Sizewell.
The Ridgeway Chase is a 60km point-to-point along the Ridgeway National Trail from Ivinghoe Beacon to Wallingford. It's a good next step once you've finished a 50K, before you take on one of our 100K ultra marathons.
Compare our 50K ultras
Median times and finish rates are from the most recent edition of each race. Click a race for the full route, checkpoints and entry details.
| Race | Next date | Distance | Climb | Time limit | Median time | Finish rate |
|---|---|---|---|---|---|---|
| Chiltern Ridge Winter 50K | Sat 31 Oct 2026 | 50km | 800m+ | 9 hours | 6:12:56 | 97% |
| North Chilterns 50K | Sat 21 Nov 2026 | 50km | 798m+ | 9 hours | 5:49:30 | 99% |
| Chiltern Ridge Classic 50K | Sat 17 Apr 2027 | 50km | 980m+ | 9 hours | 6:11:36 | 97% |
| The Ridgeway Chase | Sat 29 May 2027 | 60k | 1000m+ | 10.5 hours | 8:03:42 | 83% |
| Suffolk Coastal Path 50K | Sat 11 Sep 2027 | 50km | 120m+ | 9 hours | 6:11:48 | 98% |
Chiltern Ridge Winter 50K
Experience the autumn/winter edition of our classic Chiltern Ridge race, following a scenic single-loop 50K course starting and finishing in Berkhamsted.
North Chilterns 50K
Experience the stunning North Chiltern trails, with flowing ridgeline running and views that stretch for miles.
Chiltern Ridge Classic 50K
An iconic 50K ultra marathon in the Chiltern Hills, traversing the stunning ridgeline trails between Ivinghoe Beacon & Whiteleaf.
The Ridgeway Chase
The Ridgeway Chase is a 60km point-to-point ultramarathon following the historic Ridgeway National Trail.
Suffolk Coastal Path 50K
Run the stunning Suffolk Coastal Path from Lowestoft to Aldeburgh.
Frequently asked questions
How long is a 50K ultra marathon?
A 50K is 50 kilometres, or just over 31 miles. That's about 8km (5 miles) further than a marathon, which makes it the shortest standard ultra marathon distance.
How long does it take to run a 50K trail ultra?
At our most recent 50K races, the median finish time was between 5 hours 50 minutes and 6 hours 15 minutes. Winners finish in under 4 hours, and the final finishers usually come in after 8.5 to 9 hours. Hillier courses and muddy winter conditions add time, so most runners plan for 6 to 8 hours.
What is the best 50K for a first ultra?
All of our 50Ks have a generous 9-hour time limit, are fully marked and have regular, well-stocked checkpoints, and each year many runners complete one as their first ultra. If you want the least climbing, the Suffolk Coastal Path 50K has only around 120m of ascent (though the sand and shingle sections are tougher than they look). For a classic hilly trail ultra, choose the Chiltern Ridge Classic 50K or the Chiltern Ridge Winter 50K.
What is the cut-off time for a 50K?
Each of our 50K races has an overall 9-hour time limit, with checkpoint cut-offs along the way. That works out at an average of just under 11 minutes per kilometre, so you can comfortably walk the hills and run the flats and descents.
Do I need to qualify or have run a marathon before?
No. There are no qualifying standards for any of our 50K races. Having run a marathon, or long training runs of 25–30km on trails, will make race day much more enjoyable.
Are your 50K races UTMB Index races?
Yes. All of our 50K races are UTMB World Series Index races, so your result earns you a 50K category UTMB Index.
Will I get lost?
Our 50K routes are fully marked with our orange arrows and ribbons, and marshalled at key points. We also ask runners to carry the GPX route on a watch or phone as a backup.
Explore more races
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100K ultra marathons
The Chiltern Hills 100K and the 139km Ridgeway Challenge.
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Chilterns trail races
Every race we put on in the Chiltern Hills, from 8K to 139km.
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Ultras near London
Ultras and trail races a short train ride from London.
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All ultra marathons
All of our ultra marathons, from 50K to 139km.
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Thank you so much to you and the teams of marshals / check-point volunteers. It was my first ultra and I thoroughly enjoyed it. You created a supportive and engaging atmosphere among runners and organisers alike.
Mike
North Chilterns 50K, 2023
What a lovely first ultra! Beautiful views, well organised, a well marked course with really sweet little orange ribbons. Super friendly supportive marshalls and well stocked aid stations. Just loved it!!
Georgina
Greensand Country 50km, 2022
Keep up with the pace
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