Ironman triathlons in the UK
An Ironman or full distance triathlon is one of the toughest event formats around and only do-able by the most committed athletes with both the physical and mental endurance to cross the finish line. Also called a 140.6 triathlon or full distance triathlon, these long-distance events involve a 2.4-mile swim (3.9km), a 112-mile bike ride (180km), and a 26.2-mile run (42.2km) - a total of 140.6 miles completed in an average of around 10-15 hours. Select your location for full distance triathlons in your area or scroll down to see major events coming up.
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Full distance triathlons in 2025
Featured events are listed below - select a month/region or the map view to see all events.
- Sat 5 Jul
- £275-£295
ATW Odyssey Full 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.
- 3.8 km river swimming
- 180 km road cycling
- 26.2 miles road running
- Fri 29 - Sun 31 Aug
- £279
Full Long Course Weekend
A gruelling Ironman-style challenge set over a weekend starting with a 2.4-Mile Swim on Friday, 112-Mile Sportive on Saturday then a Marathon on Sunday, supported by the best crowds you'll ever find.
- 2.4 miles lake swimming
- 112 miles road cycling
- 26.2 miles road running
Ironman triathlons near you
Select your location for Ironman and 140.6 triathlons in your area.