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
  • £90-£250
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 + 3330 ft ascent
  • 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)
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!
  • 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 + 1625 m ascent
  • 25 km trail running + 866 m ascent
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 + 8490 ft ascent
  • 20 km road running + 3288 ft ascent
Challenge yourself to tackle a 100km Centurion this year, a distance made popular by the PTO race series. Ideal if you're training for a 70.3 Half-Iron or taking a step up from Standard Distance Tri.
  • Sun 24 May 2026
  • £120-£135
Bedford, Bedfordshire, UK

ATW Box End Centurion 100km Triathlon

Challenge yourself to tackle a 100km Centurion this year, a distance made popular by the PTO race series. Ideal if you're training for a 70.3 Half-Iron or taking a step up from Standard Distance Tri.

  • 2250 m lake swimming
  • 81 km road cycling + 1674 ft ascent
  • 20 km trail running + 340 ft ascent
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 + 1708 ft ascent
  • 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
  • £155-£175
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 + 1680 ft ascent
  • 21 km multi terrain running + 0 ft ascent
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
  • £135
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 + 2501 ft ascent
  • 21 km multi terrain running + 259 ft ascent
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
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
  • £260-£290
  • 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 + 3300 ft ascent
  • 14 miles trail running + 1300 ft ascent
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 + 957 ft ascent
  • 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
  • £130-£150
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 + 1686 ft ascent
  • 21.1 km road running

Half Ironman triathlons near you

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