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 2024/2025

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

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 17 - Sun 18 May 2025
  • £155-£160
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
Flat, fast and very popular! This open water tri comprises a swim in Regatta Lake, a relatively flat bike course and flat run laps of the lake and River Trent Path . All levels welcome, solo or relay.
  • Sun 18 May 2025
  • £50-£256.80
Nottingham, Nottinghamshire, UK

Outlaw Half Nottingham

Flat, fast and very popular! This open water tri comprises a swim in Regatta Lake, a relatively flat bike course and flat run laps of the lake and River Trent Path . All levels welcome, solo or relay.

  • 1.2 miles lake swimming
  • 56 miles road cycling
  • 13.1 miles road running
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 18 May 2025
  • £120-£139.98
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
  • 80 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 18 May 2025
  • £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.

  • 1900 m lake swimming
  • 92 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 1 Jun 2025
  • £165-£186
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 + 1844 ft ascent
  • 21 km multi terrain running + 253 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 8 Jun 2025
  • £125
Weymouth, Dorset, UK

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
Previously known as Mount Edgcumbe Triathlon, triathletes of all abilities can experience a truly exceptional coastal venue, finishers medal, t-shirt and memorable day out at a fantastic event.
  • Sun 15 Jun 2025
  • £99
Torpoint, Cornwall, UK

Plymouth Triathlon | Middle Distance

Previously known as Mount Edgcumbe Triathlon, triathletes of all abilities can experience a truly exceptional coastal venue, finishers medal, t-shirt and memorable day out at a fantastic event.

  • 1.9 km sea swimming
  • 90 km road cycling
  • 20 km trail running
Racing through the hills Kielder Forest and on hard-packed trails around the lake, this half distance triathlon is a serious test of endurance.
  • Sun 29 Jun 2025
  • £195-£210
Hexham, Northumberland, UK

The Northumbrian | Half Iron Distance

Racing through the hills Kielder Forest and on hard-packed trails around the lake, this half distance triathlon is a serious test of endurance.

  • 1.2 miles lake swimming
  • 56 miles road cycling
  • 13.1 miles trail 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 5 Jul 2025
  • £130
Saint 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
Formerly The London Triathlon, this is one of the world’s biggest triathlons where athletes will race through the capital on a landmark-filled route. London is calling!
  • Sat 2 Aug 2025
  • £264
London, UK

London T100 | 100km

Formerly The London Triathlon, this is one of the world’s biggest triathlons where athletes will race through the capital on a landmark-filled route. London is calling!

  • 2 km dock swimming
  • 80 km road cycling
  • 18 km road running
A gruelling Half Ironman-style challenge set over a weekend starting with a 1.2-Mile Swim on Friday, 56-Mile Sportive on Saturday then a Half Marathon on Sunday, supported by the best ever crowds!
  • Fri 29 - Sun 31 Aug 2025
  • £179
Masham, North Yorkshire, UK

Half Long Course Weekend

A gruelling Half Ironman-style challenge set over a weekend starting with a 1.2-Mile Swim on Friday, 56-Mile Sportive on Saturday then a Half Marathon on Sunday, supported by the best ever crowds!

  • 1.2 miles lake swimming
  • 56 miles road cycling
  • 13.1 miles road running
The Long Course Weekend challenge specifically tailored to junior athletes. Swim on Friday, cycle on Saturday and run on Sunday. Same massive crowds and the same awesome experience!
  • Fri 29 - Sun 31 Aug 2025
  • £129
Masham, North Yorkshire, UK

Junior Long Course Weekend

The Long Course Weekend challenge specifically tailored to junior athletes. Swim on Friday, cycle on Saturday and run on Sunday. Same massive crowds and the same awesome experience!

  • 1.2 miles lake swimming
  • 56 miles road cycling
  • 10 km road running
Taking THE ROC into the Lake District, this is an opportunity to test your resolve and focus in one of the most inspiring locations in Europe. Face up to the mountain.
  • Sat 6 Sep 2025
  • £210-£235
Ulverston, Cumbria, UK

THE ROC ENGLAND

Taking THE ROC into the Lake District, this is an opportunity to test your resolve and focus in one of the most inspiring locations in Europe. Face up to the mountain.

  • 1.5 km lake swimming
  • 92 km road cycling
  • 18.5 km multi terrain running
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.
  • Sun 21 Sep 2025
  • £155-£175
Maldon, Essex, UK

ATW Big East & Maldon Triathlon | 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
Scotland, you are immense. ROC Scotland athletes, you are legends! THE ROC takes on the Highlands, from Kinlochleven to the summit of Ben Nevis, the UK’s highest mountain and back.
  • Sat 4 Oct 2025
  • £220-£260
Kinlochleven, Highland, UK

THE ROC SCOTLAND

Scotland, you are immense. ROC Scotland athletes, you are legends! THE ROC takes on the Highlands, from Kinlochleven to the summit of Ben Nevis, the UK’s highest mountain and back.

  • 1.5 km lake swimming
  • 53 km mountain biking
  • 18.5 km multi terrain running

Half Ironman triathlons near you

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