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
Featured events are listed below - select a month/region or the map view to see all events.
- Sat 10 May
- £240-£260
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
- Sat 17 - Sun 18 May
- £160-£165
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
- Sun 18 May
- £120-£140
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
- Sun 18 May
- £135
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
- Sun 1 Jun
- £165-£186
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
- Sun 8 Jun
- £125
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
- Sun 15 Jun
- £99
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
- Sun 22 Jun
- £229.99-£249.99
Cardiff Legend (70.3) Triathlon
Situated in the renowned Cardiff Bay, this event stands out as a truly memorable city race. The event village and transition area are on Roald Dahl Plass in front of the Wales Millenium Centre.
- 1900 m lake swimming
- 88 km road cycling
- 21.8 km road running
- Sat 5 Jul
- £155-£175
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
- Sun 13 Jul
- £80-£95
Ripon Triathlon Festival | Standard Triathlon
One of the most popular distances within the sport of triathlon, catering to both amateur and professional athletes, striking a balance between speed and endurance.
- 1.5 km lake swimming
- 40 km road cycling
- 10 km road running
- Sun 3 Aug
- £224.99-£249.99
Craft Snowman Legend (70.3) Triathlon
Awarded the Event of the year (2021) in the Welsh Triathlon Awards, The Craft Snowman is well known as the toughest multi-terrain triathlon in the UK. It is not for the faint-hearted.
- 1900 m lake swimming
- 95 km mountain biking
- 21.1 km multi terrain running
- Fri 29 - Sun 31 Aug
- £10-£279
Long Course Weekend Yorkshire
The Long Course Weekend Yorkshire is back for a second year! A huge multi-sport festival in stunning Nidderdale featuring runs, rides, triple-style challenges and junior events too.
- Ironman
- Half Ironman
- Kids triathlon
- Lake swim 2
- Long sportive
- + 6 more races
- Sat 6 Sep
- £240-£260
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
- Sun 21 Sep
- £155-£175
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
- Sat 4 Oct
- £240-£260
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!
- 1.5 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.