The Best Ultra Marathons in the UK: A Runner's Guide to the Top Events and Organisers
- May 18
- 15 min read
By Andy Hood | Ultra and endurance runner, cancer survivor and men's wellness advocate. runningwestwardho.co.uk
In the Article
The idea to step up from marathon distance to ultra was born while I was lying in bed, not recovering from another long run or tempo effort, but from a testicular cancer operation and chemotherapy. It meant I'd have to rebuild from a long period out of my shoes, making the journey tougher than most. But that's the thing about ultras: they have a way of meeting you exactly where you are.
I wasn't interested in racing for time. Though if I'm honest, I'm extremely competitive with myself, which is exactly how it played out on the 100K London2Brighton, wanting inwardly to beat my 2023 time when I returned to the course a year later. But enough about me. If you've spent any time on this site, you'll know I write from lived experience, and that's the spirit behind this article too.
The ultra scene in the UK has exploded. Look worldwide and there is an ultra somewhere every week, often many, and your choice of what to do and where to run is almost unlimited. UK ultra marathon events in 2026 range from fully supported 100K weekend adventures along ancient paths to brutal multi-day expeditions through Scottish winter mountains, and everything in between. This isn't a guide on how to run an ultra. It's a quick reference to some of the best UK ultra marathon organisers, their most popular races, and links to get you started.
Maybe I'll see you on a start line soon.
What Is an Ultra Marathon? A Quick Guide for Beginners
Technically, an ultramarathon is any running event beyond the standard marathon distance of 26.2 miles. In practice, most UK ultras cluster around the 50K, 50-mile, 100K, and 100-mile marks, though multi-day events and 24-hour formats push things considerably further. The best ultra marathon for beginners in the UK is typically a well-supported 50K or 100K on non-technical terrain, and as you'll see below, there are organisers who have built their entire model around making that first step as welcoming as possible.
The terrain ranges from gentle chalk paths to brutal winter mountain crossings, and the entry requirements follow suit, from events that positively welcome first-timers and walkers, to those that require proof of serious prior experience just to get to the start line.
The UK is remarkably well-served. Whether you want a fully supported weekend adventure or a self-sufficient sufferfest through a Scottish winter, somebody is organising it.
The Best UK Ultra Marathon Organisers: Who's Running What
1. Ultra Challenge
Ultra Challenge is where many UK ultra runners begin their journey, and for good reason. It is the UK's biggest series of treks and trail runs, with over 40,000 participants in 2026 alone, raising over £12 million for UK charities.
I chose what I see as the classic, the original, for my first ultra: the London2Brighton 100K, a route etched into so many minds. I'd ridden London to Brighton years earlier with my Dad on the British Heart Foundation event; this time I'd run it. All 100K of it. The event, run by Ultra Challenge, was more perfect than I had imagined.
What makes Ultra Challenge unique is its genuine, deliberate inclusivity. Events are open to all, fast runners, casual runners, joggers, walkers, with distances ranging from 10K to 100K. That inclusivity creates something special: a uniquely supportive environment. This isn't the world of hyper-competitive runners who (and I say this from experience) can look down on those of us who are slower. Ultra Challengers, as you'll quickly find yourself being affectionately called, are among the most thoughtful, kind and supportive people you'll meet on any start line.
The event organisers, crew and Trek Masters set the gold standard for how to elevate a participant's experience. It is little wonder there is a strong online community, with many runners and walkers returning year after year and forming lasting friendships. For your first ultra, I cannot recommend Ultra Challenge enough.
Key Events:
London to Brighton 100K — The flagship event. From Richmond-upon-Thames, over the North Downs and through Surrey and Sussex to the Brighton coast.
Thames Path Ultra — 100K along the famous Towpath from Putney Bridge to Henley, through Richmond, Hampton Court, Runnymede, and Windsor.
Lake District Ultra — A 100K loop from Kendal, taking in the Garburn Pass, Ambleside, and the shores of Lake Windermere.
Gower Peninsula Challenge — Set on the stunning Gower Peninsula, a figure-of-eight route among golden beaches, limestone cliffs, and the grounds of Penrice Castle.
Plus 15+ more events annually, ranging from city walks to coastal challenges across England.
2. Threshold Sports / Threshold Trail Series
Founded in 2008, Threshold Sports organises some of the UK's most recognisable ultra events with a stated mission of opening up ultras to all abilities. Their Threshold Trail Series positions itself squarely in the accessible, inclusive end of the market, though their courses have real history and character beneath the welcoming surface.
In the spirit of fairness, and honesty, my own experience at Race to the Stones in 2023 (six weeks after London to Brighton) was notably different to what I'd experienced with Ultra Challenge. The atmosphere among participants wasn't as warm and the aid station crew, many of whom were agency workers, were visibly disengaged. I vowed never to return. That said, it's clear from the events' continued popularity that many thousands of runners find exactly what they're looking for at Threshold events, and the courses themselves are genuinely outstanding.
Key Events:
Race to the Stones — The flagship: 100K along the Ridgeway, Britain's oldest path, from Lewknor to the ancient Avebury Standing Stones UNESCO World Heritage Site. First run in 2013, it now attracts around 3,000 participants annually with a 90%+ completion rate. Options include a non-stop 100K, two separate 50Ks, or a weekend split with overnight basecamp.
Race to the King — A 100K following the Monarch's Way and South Downs Way to Winchester, with distances from 30K up to a non-stop 100K.
Endure24 — 24-hour trail races in Reading and Leeds where individuals or relay teams see how many 8K laps they can complete. Billed as the UK's biggest 24-hour race.
3. Centurion Running
James Elson founded Centurion Running in 2010, having raced extensively across the UK and the world. His goal was to bring the fully supported style of ultra racing he had enjoyed overseas back to British trails. The first North Downs Way events followed in 2011, and Centurion hasn't stopped since, adding a coaching arm in 2012 and a specialist store in 2013. It is now one of the most respected names in competitive UK ultra running.
Where Ultra Challenge and Threshold are built around participation and accessibility, Centurion sits at the serious end of the spectrum. These are proper races, with competitive fields, demanding cut-offs, and technical challenges that have shaped some of Britain's best ultra runners. That said, Centurion prides itself on welcoming first-time ultra runners alongside the elite, with around 25% of starters at some events being complete ultra newcomers.
Key Events:
South Downs Way 100 — 100 miles along the chalk ridgeway from Winchester to Eastbourne, with a 30-hour cut-off. One of the UK's most established 100-milers.
South Downs Way 50 — 50 miles from Worthing to Eastbourne with 5,700ft of climb. Now in its 15th year.
North Downs Way 100 — 100 miles across the historic North Downs trail in Surrey and Kent.
Centurion Track 100 — The UK's only Gold Label IAU event, held at Bedford International Athletics Stadium. At the 2021 edition, Aleksandr Sorokin set new world records at 100 miles and 12 hours.
4. UTMB World Series (UK Events)
UTMB, Ultra-Trail du Mont-Blanc, began in Chamonix in 2003, founded by Catherine and Michel Poletti. What started as a single race around Mont Blanc has grown into the world's leading trail event brand, now partnered with the Ironman Group. The flagship race covers approximately 171K with 10,000m of elevation gain through France, Italy, and Switzerland, widely regarded as one of the most competitive trail ultras on earth.
I have run the Tour du Mont Blanc twice, not as an official UTMB entrant, but independently in the week leading up to the event in 2023 and 2025, when the trails around the Chamonix valley are alive with the energy of race week. There is genuinely nothing else like it. This year I'll be returning for the full UTMB week, bringing live updates from the valley and exploring the trails around the Mont Blanc massif. Follow along on Instagram at @runningwestwardho for updates. If you're considering making the trip yourself, whether to race, to spectate, or to run the TMB independently, I've put together a complete UTMB guide covering everything you need to know.
For UK runners, UTMB is relevant on two fronts. First, many aspire to race in Chamonix itself, qualifying through the UTMB World Series points system. Second, the UK now has two events within the World Series calendar that allow runners to earn valuable qualifying "Running Stones".
UK Events:
Ultra Trail Snowdonia by UTMB — Held in May across the mountains of Snowdonia National Park. Multiple distances from 25K to 100 miles.
Arc of Attrition by UTMB — Originally created by Cornish trio MudCrew (Jane Stephens, Andy Trudgian, and Andrew Ferguson) in 2015 and sold to the UTMB World Series in 2025, the Arc has become one of the UK's most iconic winter ultras. The 100-mile flagship follows the South West Coast Path from Coverack to Porthtowan through brutal January conditions, with shorter 50-mile and 25-mile options.
I'm not usually one for winter ultras. At that time of year I'm typically in a recovery programme before building into a new training block in January ahead of spring events. But knowing a lot of people who were running the Arc this year, I headed down to Cornwall for what I call the baby Arc, the Arc25. Still a marathon distance on very muddy, technical trails that demand a serious amount from the legs, it's by no means a soft introduction. I wasn't overly pleased with my performance; I didn't feel in the best shape and the day served to reinforce exactly why I tend to stay away from winter events. That said, seeing good friends Loyd and Liga from the YouTube channel Run4Adventure on the course more than made up for it. The Arc has an atmosphere and a community that is genuinely its own, raw, elemental, and very Cornish.
5. The Spine Race
The Spine Race is in a category of its own. Founded in 2010 by Phil Hayday-Brown and Scott Gilmour, inspired by their work organising the Polar Challenge in northern Canada — the idea was to bring that same brutal, self-sufficient spirit to British soil. The Pennine Way, the backbone of England stretching from Derbyshire to the Scottish Borders, provided the perfect canvas. The name came from a drunken brainstorm in a pub. In January 2012, 15 runners started. Three finished.
Today the Spine is widely regarded as Britain's most brutal race, and its reputation has spread far beyond these shores.
Key Events:
Winter Spine Race — 268 miles non-stop along the Pennine Way in mid-January. Snow, ice, sub-zero temperatures, sleep deprivation, and 10,000m of elevation gain. There are no mandatory sleep stations. This is an expedition as much as a race.
Summer Spine Race — The same 268-mile route in summer conditions. No less serious.
Spine Challenger — A 108-mile southern section from Edale to Hardraw, offering an introduction to the concept without the full Pennine commitment.
6. Montane Lakeland 50 & 100
Lancashire-born runner Marc Laithwaite created the Lakeland races in 2008, inspired by conversations with his ultra-running friends in the mid-2000s about what a truly spectacular Lake District circuit might look like. Since that first edition, the events have raised between £60,000 and £90,000 per year for locally chosen charities, and have grown into what many consider the UK's premier trail ultra experience.
Key Events:
Montane Lakeland 100 — 105 miles in a clockwise loop starting and finishing in Coniston, taking in the Dunnerdale Fells, Eskdale, Wasdale, Buttermere, Keswick, Haweswater, Kentmere, and Ambleside. Around 6,300m of ascent. The 40-hour cut-off and 40-50% drop-out rate speak to its severity.
Montane Lakeland 50 — 55 miles from Dalemain to Coniston on the second half of the 100 route, with a 24-hour cut-off and 3,069m of ascent. A brilliant first 50-miler in a landscape that will stay with you forever.
7. Rat Race Adventure Sports
Rat Race has been helping everyday people discover extraordinary things they're capable of since 2004. Where many ultra events are competitive by nature, Rat Race explicitly isn't, they are all about finish lines, not finish times, and design every event to be genuinely achievable. Their portfolio spans UK ultras and multi-sport adventures to international expeditions across five continents.
Key Events:
The Wall — 70 miles from Carlisle Castle to Gateshead's Baltic Quay, following Hadrian's Wall country. Running since 2012 and designed to be completed at a 3mph walking pace, it has a completion rate of over 90% and is widely recommended as a first ultramarathon.
Rat Race 100 — A growing series of fully supported 100-mile point-to-point journeys: the coastal classic from Bamburgh Castle to Edinburgh, and a newer Edinburgh to Glamis Castle route through St Andrews and rolling Angus countryside.
Scotland Coast to Coast — A multi-sport adventure combining trail running, cycling, and kayaking across Scotland from east to west.
8. Ultra X
Ultra X was born from a chance meeting. Co-founders Sam Heward and Jamie Sparks met during a five-day race in the deserts of Jordan in 2017, and over breakfast after the final stage, found themselves convinced that multi-day stage racing could be made accessible to athletes of all levels. They co-directed their first event in Jordan in 2018 — the Wadi Rum Ultra, with 35 finishers, and by 2019 had rebranded it as Ultra X Jordan, the first race in a series that now spans eight countries across four continents.
In 2026, Ultra X made headlines in the UK ultra community when they acquired the Dragon's Back Race and the Northern Traverse out of administration following the sudden collapse of long-standing organiser Ourea Events. Both events will remain entirely separate brands from Ultra X, with former Ourea Operations Director Greg Mickelborough joining the group to lead delivery, and former Ourea CEO Shane Ohly contracted to ensure continuity.
For runners who had feared losing two of the most iconic events in British ultra running, it was the best possible outcome.
Key Events:
Dragon's Back Race — A legendary 380K, six-day ultra running journey down the spine of Wales, with 16,400m of ascent. Widely considered one of the toughest mountain races in the world. New for 2026, shorter two-day options include Dragon's Fire (northern Wales, starting at Conwy Castle) and Dragon's Tail (southern Wales, finishing in Cardiff).
Northern Traverse — 300K coast-to-coast from St Bees on the Cumbrian coast to Robin Hood's Bay in North Yorkshire. 2026 entries have been transferred to 2027.
Ultra X International Series — Multi-stage events in Jordan, Rwanda, Tanzania, the Azores, Finland, South Africa, and beyond.
9. Montane Trail Series
Not everything in this guide needs to be an ultra, and the Montane Trail Series is worth including precisely because it isn't. This is a well-established series of trail races across the UK, typically at 10K, half marathon, and marathon distances — organised by Montane, the outdoor apparel brand whose name also graces the Lakeland 100 and Spine Race. The events are held in some of Britain's most spectacular landscapes and are an excellent way to build trail-specific fitness and experience before stepping up to ultra distance. If you're a road runner looking to make the move to trails, or simply want a well-organised race in beautiful surroundings without the commitment of an ultra, the Montane Trail Series is a natural starting point.
10. UK Ultra
Not every great ultra organiser operates on a national scale, and UK Ultra is a good reminder that some of the best experiences come from smaller, runner-led operations. Based in the South Downs National Park and run by runners, for runners, UK Ultra puts on well-organised, friendly events on non-technical but spectacular terrain, making them particularly well-suited to anyone looking for their first trail ultra without the logistical complexity of larger events. If the South Downs are on your doorstep, or you're looking for a stepping stone to bigger challenges, they're well worth a look.
The UK Ultra Scene in 2026: What's Changed and What to Know
The UK ultra scene is not without turbulence. In early 2026, Ourea Events, the company behind the Dragon's Back Race, Cape Wrath Ultra, Northern Traverse, and Skyline Scotland, ceased trading with immediate effect, a casualty of financial pressures that had their roots in COVID-era cancellations. It was a significant blow.
Fortunately, as noted above, Ultra X stepped in to secure Dragon's Back and Northern Traverse. Cape Wrath Ultra's future, however, remains uncertain at the time of writing.
It's a reminder that even the most beloved events aren't guaranteed to continue, and that the organisers who do this well, who build communities, treat participants like people rather than entries, and genuinely care about the experience, are worth supporting.
Frequently Asked Questions
What is the best ultra marathon in the UK for beginners?
Ultra Challenge events, particularly the London2Brighton 100K and Thames Path Ultra, are widely regarded as the best starting point for first-time ultra runners in the UK. They offer multiple distances (10K, 25K, 50K, 100K), exceptional support, and a genuinely welcoming community atmosphere. Rat Race's The Wall (70 miles along Hadrian's Wall) is another excellent first ultra, with a 90%+ completion rate and a philosophy built entirely around finishing rather than racing. From personal experience, Ultra Challenge is the gold standard for anyone stepping up from marathon to ultra distance.
How do I enter an ultra marathon in the UK?
Most UK ultra marathons open entries via their own websites, often months or even a year in advance. Popular events like the Dragon's Back Race, Centurion 100-milers, and Montane Lakeland 100 sell out quickly, sometimes within hours of opening. For UTMB World Series events, you also need to accumulate qualifying "Running Stones" through other World Series races before you can enter certain distances. Always check entry requirements, cut-off times, and any mandatory kit lists before signing up.
What distance is a UK ultra marathon?
Any race beyond the standard marathon distance of 26.2 miles (42.2K) qualifies as an ultra. In the UK, the most common distances are 50K, 50 miles, 100K, and 100 miles, though events range from 30K all the way to multi-day, multi-hundred-mile challenges like the 268-mile Spine Race along the Pennine Way.
How long does it take to train for an ultra marathon?
This depends heavily on your current fitness base and the distance you're targeting. As a general guide, runners with a solid marathon background typically need 12–20 weeks of structured training for a supported 50K or 100K. For 50-mile and 100-mile events, most coaches recommend a minimum 20–24 week build, with significant time on feet over varied terrain. My own blog at runningwestwardho.co.uk includes a real-world training series for first-time 100K runners, including the highs and lows of the process.
What is the hardest ultra marathon in the UK?
The Montane Spine Race is widely considered the toughest ultra marathon in the UK, and one of the most extreme in the world. It covers 268 miles non-stop along the Pennine Way in mid-January, with no mandatory sleep stations, sub-zero temperatures, and over 10,000m of elevation gain. Completion rates are low and the event has become a global benchmark for self-sufficiency and endurance. The Dragon's Back Race (380K over six days through the mountains of Wales) and the Cape Wrath Ultra are also contenders for the title.
What should I wear and carry for a UK ultra marathon?
Kit requirements vary significantly between events. Inclusive, supported events like Ultra Challenge provide fully stocked aid stations and require minimal mandatory kit. Technical mountain events like the Spine Race, Dragon's Back, and Centurion 100s require extensive mandatory kit lists covering navigation, emergency shelter, first aid, and waterproofs. Always download the specific event's mandatory kit list and brief well in advance. Trail shoes with good grip are essential for almost all UK off-road ultras; road shoes are rarely appropriate.
Are UK ultra marathons suitable for walkers?
Absolutely, many UK ultras actively welcome walkers, particularly those in the Ultra Challenge, Rat Race, and Threshold series. Ultra Challenge events in particular are designed for walkers as much as runners, with generous cut-off times and route options at every distance. If you're a walker considering your first ultra, start with a 50K or 100K Ultra Challenge event, the community you'll find there is unlike anything else in endurance sport.
How much do UK ultra marathons cost to enter?
Entry fees vary widely. Smaller, community-run events can cost as little as £30–60. Mid-range supported events like Ultra Challenge and Threshold typically cost £80–£150 for 50K distances and £150–£250 for 100K. Premium or expedition-style events, Dragon's Back Race, Spine Race, Cape Wrath Ultra, can cost £400–£900+ due to the logistical complexity involved. Multi-day international events through Ultra X range from £500 upwards.
What UK ultra marathons can I do without previous ultra experience?
Several UK ultras are explicitly designed for first-timers with no previous ultra experience. Ultra Challenge events require no prior ultra history and welcome complete newcomers. Rat Race's The Wall is another great entry point. Threshold's Race to the Stones is achievable for fit runners stepping up from marathon distance. Some events may ask for evidence of previous distance running (marathon or half marathon times) at minimum, so having a race history helps with entry even if ultra experience isn't required.
What has happened to Ourea Events and the Cape Wrath Ultra?
Ourea Events, organisers of the Dragon's Back Race, Northern Traverse, Cape Wrath Ultra, and Skyline Scotland, went into administration in early 2026. Ultra X subsequently acquired the Dragon's Back Race and Northern Traverse, both of which will continue as independent brands. The Cape Wrath Ultra's future remains uncertain at the time of publication. Always check the relevant event websites for the latest status.
Go find your start line. You can follow my own journey, race reports, training, fundraising for cancer and mental health charities, at runningwestwardho.co.uk.
All website links correct at time of publication. Always check event websites directly for current dates, distances and entry requirements.
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