100 Mile Ultra Marathons in the UK

🎉 New Kit List Available 🎉 - View Here

100 MILE ULTRA MARATHONS 2026 - 2027

For serious ultra-runners, completing a 100 mile race is a defining achievement. This curated 2026 - 2027 UK 100 mile ultra marathon calendar offers the ultimate test of physical and mental fortitude, set against the breath taking backdrops of the British Isles. From the historic trails of the South Downs Way and challenging routes through the Peak District to the rugged beauty of the Scottish Highlands and Welsh mountains, each 100-mile ultra presents a unique adventure. Whether you're aiming for a personal best, a Grand Slam or simply to experience the profound journey of covering a hundred miles on foot, this is your definitive resource for finding your next 100 mile ultra marathon in the UK.

Clear Filters

24 events found

Map View

100 Miles

Centurion North Downs Way 100

Distance: 103 Miles

Elevation: 3,350M

Location: Farnham, Surrey

Date: Sat, 8th Aug 2026

More Event Info

100 Miles

Snowdon Ultra 100

Distance: 102 Miles

Elevation: 5,788M

Location: Snowdonia Eryri

Date: Sat, 5th Sep 2026

More Event Info

100 Miles

Robin Hood 100

Distance: 100 Miles

Elevation: 1,302M

Location: Retford, Nottinghamshire

Date: Sat, 12th Sep 2026

More Event Info

100 Miles

Peak District Challenge 100 Miler

Distance: 100 Miles

Elevation: 4,800M

Location: Hathersage, Derbyshire

Date: Fri, 18th Sep 2026

More Event Info

100 Miles

Cotswold Way Century

Distance: 102 Miles

Elevation: 3,688M

Location: Chipping Campden, Cotswolds

Date: Sat, 19th Sep 2026

More Event Info

100 Miles

13 Valleys Ultra

Distance: 114 Miles

Elevation: 7,000M

Location: Keswick, Lake District

Date: Fri, 25th Sep 2026

More Event Info

100 Miles

Cheshire Ring 100 Miler

Distance: 100 Miles

Elevation: 345M

Location: Manchester

Date: Sat, 26th Sep 2026

More Event Info

100 Miles

Pilgrims Ultra 100 Miler

Distance: 100 Miles

Elevation: 2,133M

Location: Holy Island, Lindisfarne

Date: Sat, 26th Sep 2026

More Event Info

100 Miles

South Hams 100 Mile Ultra

Distance: 100 Miles

Elevation: 4,890M

Location: Plymouth

Date: Sat, 10th Oct 2026

More Event Info

100 Miles

Centurion Autumn 100

Distance: 100 Miles

Elevation: 1,500M

Location: Goring, Reading

Date: Sat, 17th Oct 2026

More Event Info

100 Miles

South Downs 100 Miler

Distance: 100 Miles

Elevation: 3,718M

Location: Plumpton, East Sussex

Date: Mon, 26th Oct 2026

More Event Info

100 Miles

Slate Trail Ultra

Distance: 91 Miles

Elevation: 3,900M

Location: Porth Penrhyn, Wales

Date: Sat, 14th Nov 2026

More Event Info

100 Miles

Arc Of Attrition 100

Distance: 107 Miles

Elevation: 5,500M

Location: Coverack, Cornwall

Date: Fri, 22nd Jan 2027

More Event Info

100 Miles

Yellow Belly 100 Miler

Distance: 100 Miles

Elevation: 2,438M

Location: Swallow. Lincolnshire

Date: Sat, 27th Mar 2027

More Event Info

100 Miles

Chester Ultra 100

Distance: 102 Miles

Elevation: 849M

Location: Chester

Date: Sat, 17th Apr 2027

More Event Info

100 Miles

Thames Ring 100

Distance: 100 Miles

Elevation: -

Location: Nether Heyford, Northampton

Date: Fri, 23rd Apr 2027

More Event Info

100 Miles

Centurion Thames Path 100

Distance: 100 Miles

Elevation: 560M

Location: Richmond, London

Date: Sat, 1st May 2027

More Event Info

100 Miles

Epona 100 Mile Ultra

Distance: 101 Miles

Elevation: 5,181M

Location: Abergavenny, Wales

Date: Sat, 8th May 2027

More Event Info

100 Miles

Ultra Scotland 100

Distance: 104 Miles

Elevation: 4,611M

Location: St Johns

Date: Sat, 5th Jun 2027

More Event Info

100 Miles

Hardmoors 110

Distance: 110 Miles

Elevation: 5,000M

Location: Filey, North Yorkshire

Date: Sat, 5th Jun 2027

More Event Info

100 Miles

The Round 100

Distance: 103 Miles

Elevation: 1,465M

Location: Beacon Hill Country Park, Leicestershire

Date: Sat, 5th Jun 2027

More Event Info

100 Miles

Centurion South Downs Way 100

Distance: 100 Mile

Elevation: 3,800M

Location: Winchester, Hampshire

Date: Sat, 12th Jun 2027

More Event Info

100 Miles

West Highland Way Race

Distance: 95 Miles

Elevation: 4,267M

Location: Milngavie Station, Scotland

Date: Sat, 19th Jun 2027

More Event Info

100 Miles

Beacons Way Ultra 100 Miles

Distance: 100 Miles

Elevation: 6,143M

Location: Brecon Beacons

Date: Sat, 24th Jul 2027

More Event Info

100 MILE ULTRA MARATHON CALENDAR 2026 - 2027

Taking on a 100 mile ultra is a serious undertaking, but the reward is an experience you'll never forget! It’s a distance that redefines your limits and connects you with an incredible community of runners who understand the dedication it takes to get to the start line, let alone the finish.

View the 2026 - 2027 100 mile ultra marathon calendar to find the best 100-mile ultras across the UK!

Running Gear Reviews

Shoes

Kailas Fuga EX330 Review

We test this Tor des Geants-inspired ultra shoe to see if its Vibram grip is worth the £150 price…

Keep Reading

Gear

SunGod Classics⁴ PRO Sunglasses Review

We put the new SunGod Classics4 PRO sunglasses to the test to see how they hold up for ultrarunning.

Keep Reading

Gear

Nitecore UT27 vs UT6 Head Torch Review

Hands-on review of the Nitecore UT27 and UT6 head torches. Which one will guide me through the Race…

Keep Reading

Gear

FLEXTAIL Zero Power Bank Review

We test the FLEXTAIL Zero Power Bank against two of the UKs toughest 100 mile ultramarathons.

Keep Reading

Nutrition

Awesome Supplements Hydrate + Endure Review

Awesome Supplements Hydrate + Endure bundle tried and tested at the brutal UTS 100k ultra.

Keep Reading

Shoes

Mount to Coast C1 Review

We've been testing out Mount to Coasts latest long-distance super shoe to see how it performs on…

Keep Reading

View More Reviews

100 MILER FAQs

How do I know if I'm ready to take on a 100 miler?

There’s no magic formula, but a solid base of experience is key. Most race organisers will require you to have completed a 50 mile ultra marathon (or sometimes longer) within the last 12-18 months. Beyond race results, it’s about your personal journey. Are you comfortable running through the night? Have you tested your nutrition and gear on long training runs? Are you mentally prepared for the inevitable highs and lows? If you’ve got a few 50-milers under your belt and the hunger for a bigger challenge, you’re likely ready to start training.

How should I choose my first 100 mile race from this list?

Think about what plays to your strengths and what kind of experience you want. Consider these three things:

Terrain: Do you love technical, hilly routes, or would you prefer a flatter, faster course to build confidence? Elevation gain is a huge factor in a race's difficulty.
Navigation: Are you a skilled navigator or would you prefer a well-marked course? Many UK 100-milers require you to use a GPX file on a watch or device.
Logistics: A lapped course can be simpler for a first attempt as you pass your drop bag and crew multiple times. A point-to-point race is a grander adventure but requires more planning.

Read the race descriptions, check out a few race reports online and find one that excites you!

What is a mandatory kit list and why is it so important?

Most ultra marathons have a mandatory kit list which is a set of specific items you must carry with you at all times during the race. In the UK, this is a crucial safety measure. Our weather is famously unpredictable, and a full waterproof body cover, hat, gloves, headtorch and emergency foil blanket can be lifesaving if you get into trouble. Race organisers perform kit checks and you will be disqualified for not carrying the required items. Always check the official race website for the most up-to-date kit list.

What's the difference between having a crew and using drop bags?

A crew is your personal support team (usually friends or family) who meet you at designated checkpoints to help with nutrition, gear changes and moral support. A drop bag is a bag you prepare yourself and give to the race organisers at the start. They transport it to a specific checkpoint (often around the halfway mark), allowing you to access spare kit, food, and other supplies without needing a crew. Most races allow drop bags but crew access can be limited.

How do I enter a 100 mile ultra marathon?

GB Ultra Runner is a race directory designed to help you discover great ultras across the UK. To enter an event, you need to click the red View Race Website button on the listing, which will take you directly to the official race website. There you'll find all the details about the entry process, prices and dates.

Is the race information on this page always up to date?

I do my best to keep all information, such as dates and elevation, as accurate as possible. However, race organisers can and do make changes. Your single source of truth should always be the official race website. Please double-check all details with the organiser before making any plans or entering a race.

Filter Races

100 Mile Ultra Marathons UK

Find Your Next 100 Miler Here

100 MILE ULTRA MARATHONS 2026 - 2027

Centurion North Downs Way 100

Snowdon Ultra 100

Robin Hood 100

Peak District Challenge 100 Miler

Cotswold Way Century

13 Valleys Ultra

Cheshire Ring 100 Miler

Pilgrims Ultra 100 Miler

South Hams 100 Mile Ultra

Centurion Autumn 100

South Downs 100 Miler

Slate Trail Ultra

Arc Of Attrition 100

Yellow Belly 100 Miler

Chester Ultra 100

Thames Ring 100

Centurion Thames Path 100

Epona 100 Mile Ultra

Ultra Scotland 100

Hardmoors 110

The Round 100

Centurion South Downs Way 100

West Highland Way Race

Beacons Way Ultra 100 Miles

100 MILE ULTRA MARATHON CALENDAR 2026 - 2027

Running Gear Reviews

Kailas Fuga EX330 Review

SunGod Classics⁴ PRO Sunglasses Review

Nitecore UT27 vs UT6 Head Torch Review

FLEXTAIL Zero Power Bank Review

Awesome Supplements Hydrate + Endure Review

Mount to Coast C1 Review

100 MILER FAQs

How do I know if I'm ready to take on a 100 miler?

How should I choose my first 100 mile race from this list?

What is a mandatory kit list and why is it so important?

What's the difference between having a crew and using drop bags?

How do I enter a 100 mile ultra marathon?

Is the race information on this page always up to date?

Got your mandatory kit sorted?