Half Ironman triathlons

Half Ironman triathlons

Middle distance (aka 70.3) triathlon events | 1.2 mile swim + 56 mile bike + 13.1 mile run

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Half Ironman triathlons in the UK

Completing a Half Ironman is a real feat of endurance but is do-able if you are willing to put in the training time. Also called a 70.3 triathlon or middle distance triathlon, these long-distance events involve a 1.2-mile swim (1.9km), a 56-mile bike ride (90km), and a 13.1-mile run (21.1km) - a total of 70.3 miles completed in an average of around 6 hours. Select your location for 70.3 triathlons in your area or scroll down to see major events coming up.

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70.3 triathlons in 2025/2026

Featured events are listed below - select a month/region or the map view to see all events.

The totally unique ROC format, from Abersoch Bay to the top of Wales’ highest mountain and back. Swim, Bike, Mountain, Bike, Run; THE ROC WALES is triathlon - tough and redefined.
  • Sat 9 May 2026
  • £250-£270
Pwllheli, Gwynedd, UK

THE ROC WALES

The totally unique ROC format, from Abersoch Bay to the top of Wales’ highest mountain and back. Swim, Bike, Mountain, Bike, Run; THE ROC WALES is triathlon - tough and redefined.

  • 1.5 km sea swimming
  • 100 km road cycling
  • 13 km multi terrain running
  • Recycling
  • Plastic bottle free
  • Entertainment
  • Music
  • Chip timing
  • Enter online
  • Hilly
  • Mountainous
  • Event village
  • Event expo
  • Coast
  • Mountains
  • Sustainability policy
  • Plastic-free event
  • Age 18 & over
  • Half Ironman (middle distance)
The Big East and Maldon Triathlon is brought to you by the largest triathlon organiser in the UK! A great experience featuring a tidal river swim.
  • Sat 16 May 2026
  • £158-£178
Maldon, Essex, UK

Big East Middle Distance Triathlon

The Big East and Maldon Triathlon is brought to you by the largest triathlon organiser in the UK! A great experience featuring a tidal river swim.

  • 1500 m river swimming
  • 86 km road cycling
  • 20 km trail running
This triathlon returns for another successful year! It’s a superb swimming venue with quiet rolling roads for the bike course and a cracking run too. Plus there's lakeside camping available too.
  • Sun 17 May 2026
  • £135
Lifton, Devon, UK

Roadford Lake Triathlon | Middle Distance

This triathlon returns for another successful year! It’s a superb swimming venue with quiet rolling roads for the bike course and a cracking run too. Plus there's lakeside camping available too.

  • 1.9 m lake swimming
  • 93 km road cycling
  • 20 km road running
Conquer the ATW Centurion 100km Triathlon at Box End Lake — a thrilling endurance challenge featuring pristine open water, fast bike laps, scenic trails and unbeatable support.
  • Sun 24 May 2026
  • £117-£137
Bedford, Bedfordshire, UK

ATW Box End Centurion 100km Triathlon

Conquer the ATW Centurion 100km Triathlon at Box End Lake — a thrilling endurance challenge featuring pristine open water, fast bike laps, scenic trails and unbeatable support.

  • 2250 m lake swimming
  • 81 km road cycling
  • 20 km trail running
Race through the beautiful grounds and surrounding area of stunning South Galway in a triathlon for a range of levels then celebrate with friends and family in the festival village.
  • Sun 24 May 2026
  • £196-£245
Gort, Ireland

Lough Cutra Castle | Gauntlet Triathlon

Race through the beautiful grounds and surrounding area of stunning South Galway in a triathlon for a range of levels then celebrate with friends and family in the festival village.

  • 1.9 km lake swimming
  • 96 km road cycling
  • 21 km road running
Race through the beautiful grounds and surrounding area of the stunning Château de Chantilly in the Gauntlet Half Iron Triathlon then celebrate with friends and family in the festival village.
  • Sun 7 Jun 2026
  • £196-£245
Chantilly, France

Chateau de Chantilly | Gauntlet Triathlon

Race through the beautiful grounds and surrounding area of the stunning Château de Chantilly in the Gauntlet Half Iron Triathlon then celebrate with friends and family in the festival village.

  • 1.9 km lake swimming
  • 90 km road cycling
  • 21 km road running
Take on a superb middle distance triathlon at the fantastic Grafham Water. Suitable for all abilites, with a challenging, but achievable course, and custom medal at the finish line.
  • Sun 7 Jun 2026
  • £160-£180
Huntingdon, Cambridgeshire, UK

ATW Grafman Middle Distance Triathlon

Take on a superb middle distance triathlon at the fantastic Grafham Water. Suitable for all abilites, with a challenging, but achievable course, and custom medal at the finish line.

  • 1900 m lake swimming
  • 90 km road cycling
  • 21 km multi terrain running
The Middle Distance Triathlon will not fail to impress. With stunning views of Weymouth nature reserve and a true test of stamina, you'll be beaming with pride at the finish line.
  • Sun 14 Jun 2026
  • £155-£195
Weymouth, Dorset, UK

Weymouth WMD Triathlon | Weymouth Middle Distance Triathlon

The Middle Distance Triathlon will not fail to impress. With stunning views of Weymouth nature reserve and a true test of stamina, you'll be beaming with pride at the finish line.

  • 1900 m sea swimming
  • 90 km road cycling
  • 21 km multi terrain running
Dive into the Plymouth Middle Distance Triathlon! A stunning sea swim, scenic coastal bike ride, and flat waterfront run offering an unforgettable multisport challenge for athletes of all abilities.
  • Sun 14 Jun 2026
  • £130
Torpoint, Cornwall, UK

Plymouth Middle Distance Triathlon

Dive into the Plymouth Middle Distance Triathlon! A stunning sea swim, scenic coastal bike ride, and flat waterfront run offering an unforgettable multisport challenge for athletes of all abilities.

  • 1900 m sea swimming
  • 90 km road cycling
  • 20 km trail running
Get active in the beautiful grounds and surrounding area of stunning Cheshire in the epic Gauntlet! Bring your friends and celebrate completing your challenge in the festival village.
  • Sun 21 Jun 2026
  • £196-£245
Malpas, Cheshire, UK

Cholmondeley Castle | Gauntlet Triathlon

Get active in the beautiful grounds and surrounding area of stunning Cheshire in the epic Gauntlet! Bring your friends and celebrate completing your challenge in the festival village.

  • 1.9 km lake swimming
  • 84 km road cycling
  • 21 km road running
Get ready for one of the UK’s most exciting Half Iron triathlons of the year! Dive into crystal-clear lake waters, then ride a smooth, rolling bike course and follow scenic on-site run paths.
  • Sun 5 Jul 2026
  • £140-£160
Bedford, Bedfordshire, UK

ATW Odyssey At Box End Triathlon | Half Distance Triathlon

Get ready for one of the UK’s most exciting Half Iron triathlons of the year! Dive into crystal-clear lake waters, then ride a smooth, rolling bike course and follow scenic on-site run paths.

  • 2250 m lake swimming
  • 96 km road cycling
  • 20 km road running
A one-of-a-kind triathlon adventure from castle to coast – swim, bike, run and soak up the best of the North and South Downs, fully supported all the way, no navigation needed!
  • Sat 18 Jul 2026
  • £265-£293
  • Early bird
Windsor, Buckinghamshire, UK

Castle To Coast Triathlon

A one-of-a-kind triathlon adventure from castle to coast – swim, bike, run and soak up the best of the North and South Downs, fully supported all the way, no navigation needed!

Early bird on now

  • 1.2 miles lake swimming
  • 66 miles road cycling
  • 14 miles trail running
A jewel in the castle crown! Get active in the beautiful grounds and surrounding area of stunning Leicestershire in the epic Gauntlet Triathlon! Celebrate in the festival village afterwards.
  • Sun 19 Jul 2026
  • £196-£245
Grantham, Leicestershire, UK

Belvoir Castle | Gauntlet Triathlon

A jewel in the castle crown! Get active in the beautiful grounds and surrounding area of stunning Leicestershire in the epic Gauntlet Triathlon! Celebrate in the festival village afterwards.

  • 1.9 km lake swimming
  • 90 km road cycling
  • 21 km road running
Complete your own Odyssey on a journey of self-discovery in the Cambridgeshire countryside featuring a swim in the River Ouse, a scenic ride and a run around the beautiful town of St Neots.
  • Sat 8 Aug 2026
  • £145-£165
St. Neots, Cambridgeshire, UK

ATW Odyssey Half Distance Triathlon

Complete your own Odyssey on a journey of self-discovery in the Cambridgeshire countryside featuring a swim in the River Ouse, a scenic ride and a run around the beautiful town of St Neots.

  • 1900 m river swimming
  • 90 km road cycling
  • 21.1 km road running
Be part of a UK first. This isn’t just a Half Iron triathlon - it’s the first event of its kind where you decide the distance, from sprint to full, and race your way.
  • Sat 8 Aug 2026
  • £145-£165
St. Neots, Cambridgeshire, UK

ATW First To Full Triathlon Festival | Half Distance Triathlon

Be part of a UK first. This isn’t just a Half Iron triathlon - it’s the first event of its kind where you decide the distance, from sprint to full, and race your way.

  • 1900 m river swimming
  • 90 km road cycling
  • 21.1 km road running
Take on a wild Scottish adventure combining a cold-water loch swim, epic gravel ride and tough mountain run through the breathtaking landscape of the Arrochar Alps.
  • Sat 22 Aug 2026
  • £250
Cairndow, Argyll and Bute, UK

THE RESTLESS Gravel XTRI

Take on a wild Scottish adventure combining a cold-water loch swim, epic gravel ride and tough mountain run through the breathtaking landscape of the Arrochar Alps.

  • 1.8 km lake swimming
  • 50 km gravel riding
  • 25 km fell running
  • Chip timing
  • Enter online
  • GPS tracking
  • Hilly
  • Mountainous
  • Traffic free
  • Event village
  • Event expo
  • Rural
  • Mountains
  • Age 18-100
  • Half Ironman (middle distance)
A superb triathlon venue which hosted Ironman 70.3 for ten years! Experience dramatic hills, pristine open water and wild Exmoor scenery in a tough, rewarding Middle Distance Triathlon.
  • Sun 30 Aug 2026
  • £130
Dulverton, Somerset, UK

Wimbleball Middle Distance Triathlon

A superb triathlon venue which hosted Ironman 70.3 for ten years! Experience dramatic hills, pristine open water and wild Exmoor scenery in a tough, rewarding Middle Distance Triathlon.

  • 1900 m lake swimming
  • 92 km road cycling
  • 21 km road running
Face up to the mountain in one of Europe's most inspiring locations. From Windermere to Coniston to summit England's highest mountain, if you love a tough and rewarding challenge - you'll thrive.
  • Sat 5 Sep 2026
  • £215-£260
Ulverston, Cumbria, UK

THE ROC ENGLAND

Face up to the mountain in one of Europe's most inspiring locations. From Windermere to Coniston to summit England's highest mountain, if you love a tough and rewarding challenge - you'll thrive.

  • 1.5 km lake swimming
  • 92 km road cycling
  • 18.5 km multi terrain running
  • Recycling
  • Plastic bottle free
  • Music
  • Chip timing
  • Enter online
  • Mountainous
  • Event village
  • Rural
  • Mountains
  • Sustainability policy
  • Plastic-free event
  • Age 18 & over
  • Half Ironman (middle distance)
THE ROC takes in the Highlands. Kinlochleven to the summit of Ben Nevis and back, including a Loch swim, stunning mountain/gravel bike sections and the UK's highest mountain!
  • Sat 3 Oct 2026
  • £215-£260
Kinlochleven, Highland, UK

THE ROC SCOTLAND

THE ROC takes in the Highlands. Kinlochleven to the summit of Ben Nevis and back, including a Loch swim, stunning mountain/gravel bike sections and the UK's highest mountain!

  • 1 km lake swimming
  • 52 km mountain biking
  • 18 km multi terrain running
  • Recycling
  • Plastic bottle free
  • Music
  • Chip timing
  • Enter online
  • Hilly
  • Mountainous
  • Event village
  • Rural
  • Mountains
  • Sustainability policy
  • Plastic-free event
  • Age 18 & over
  • Half Ironman (middle distance)
  • Sat 16 - Sun 17 May 2026
  • £165-£170
Keswick, Cumbria, UK

Keswick Mountain Festival | Keswick Conqueror

A lake swim, a trail run and a road ride over the course of the festival weekend. Conquer a triathlon challenge over two days. Includes Full Weekend Festival Ticket in the price!

  • 3.6 km lake swimming
  • 100 km road cycling
  • 25 km trail running

Half Ironman triathlons near you

Select your location for Half Ironman and 70.3 triathlons in your area.

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Sleep well

A good night's sleep is an essential foundation for a healthy lifestyle, effective training and weight control.

Train slow

Low-intensity training is easier for you, reduces the risk of injury and helps builds an efficient aerobic system.

Eat natural

Cut out sugar & junk food, reduce carbs, eat natural foods and train your body to burn fat for fuel.

Get outdoors

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