Best 70.3 races in the United Kingdom

21 rated races, ranked by an overall score built from racer reviews and race reports. How we score

70.3

21 races

1. TriBourne (IronBourne) Middle Distance, Eastbourne
Eastbourne, United Kingdom
Next race 11 Jul 2027
Overall score 4.7
Excellent
#3 of 221
Strong evidence · 10 sources
1. TriBourne (IronBourne) Middle Distance, Eastbourne
Overall score 4.7ExcellentStrong evidence · 10 sourcesTop 2%#3 of 221 overall
Eastbourne, United Kingdom · Next race 11 Jul 2027
Racers loveRolling start by jumping off Eastbourne Pier, with a current-assisted sea swim
Watch outOpen roads with some narrow, twisting sections and occasional traffic
Best
Race 5.0
Weakest
Bike 3.5
2. Lakesman Half
Keswick, United Kingdom
Next race 20 Jun 2027
Overall score 4.5
Excellent
#5 of 221
Moderate evidence · 7 sources
Bike climb 722 m (2,370 ft)
2. Lakesman Half
Overall score 4.5ExcellentModerate evidence · 7 sourcesTop 3%#5 of 221 overall
Keswick, United Kingdom · Next race 20 Jun 2027
Racers loveSwim in Derwentwater beneath Skiddaw in the Lake District
Watch outCold lake at about 18 to 19 °C (64 to 66 °F) and a crowded two-wave start
“This has to be my favourite race of the year.” Racecheck reviewers, Racecheck: The Lakesman Triathlon
Bike climb
722 m (2,370 ft)
Field
about 1,200
Best
Race 5.0
Weakest
Stay and travel 3.0
Not a standard 70.3
3. The Gauntlet at Cholmondeley Castle
Malpas, United Kingdom
Next race 26 Jun 2027
Overall score 4.2
Very good
#15 of 221
Strong evidence · 13 sources
3. The Gauntlet at Cholmondeley Castle
Overall score 4.2Very goodStrong evidence · 13 sourcesTop 7%#15 of 221 overall
Malpas, United Kingdom · Next race 26 Jun 2027
Not a standard 70.3 · 1.9 / 96 / 21 km
Racers loveQuiet, fast Cheshire lanes in short 14 km (8.7 mi) laps passing through the castle grounds
Watch outShallow, weedy lake: reviewers across 2023 to 2026 complain about poor water quality
Best
Race 4.5
Weakest
Swim 3.2
Not a standard 70.3
4. Titan Brecon Middle Distance Triathlon
Tredegar, United Kingdom
Next race 12 Jun 2027
Overall score 4.2
Very good
#16 of 221
Strong evidence · 10 sources
4. Titan Brecon Middle Distance Triathlon
Overall score 4.2Very goodStrong evidence · 10 sourcesTop 8%#16 of 221 overall
Tredegar, United Kingdom · Next race 12 Jun 2027
Not a standard 70.3 · 1.9 / 96.6 / 21.1 km
Racers loveLake swim around an island is easy to sight and described as clean and warm
Watch outHilly bike of 96.6 km (60 mi), about 7 km (4 mi) over standard
“do train for hills” RaceCheck: Justin A.
Best
Swim 4.4
Weakest
Conditions 3.0
5. IRONMAN 70.3 Swansea
Swansea, United Kingdom
Next race 11 Jul 2027
Overall score 4.1
Very good
#18 of 221
Moderate evidence · 9 sources
Water 16–24 °C (61–75 °F)
5. IRONMAN 70.3 Swansea
Overall score 4.1Very goodModerate evidence · 9 sourcesTop 8%#18 of 221 overall
Swansea, United Kingdom · IRONMAN · Next race 11 Jul 2027
Racers loveCalm, enclosed dock swim with long straights
Watch outHilly bike with rough patches, cattle grids and cattle on course in 2026
“the surface over the bridge is really sharp” Enduraprep (Owain Bennett)
Water
16–24 °C (61–75 °F)
Air
12–29 °C (54–84 °F)
Field
about 2,700
Best
Run 4.4
Weakest
Conditions 3.6
6. Cotswold Classic Middle Distance
Cirencester (Cotswold Water Park, Ashton Keynes), United Kingdom
Last race 12 Jul 2026
Overall score 4.0
Very good
#24 of 221
Moderate evidence · 5 sources
6. Cotswold Classic Middle Distance
Overall score 4.0Very goodModerate evidence · 5 sourcesTop 11%#24 of 221 overall
Cirencester (Cotswold Water Park, Ashton Keynes), United Kingdom · Last race 12 Jul 2026
Racers loveRaceCheck average of 4.81 from 159 reviews, with top marks for water quality and marshals
Watch outBike surface was poor in places, with unmarked hazards, in 2020
“extremely well organised, brilliantly marshalled” RaceCheck - Paul B.
Best
Race 5.0
Weakest
Bike 2.3
7. ATW Grafman Middle Distance Triathlon
Grafham, United Kingdom
Next race 6 Jun 2027
Overall score 4.0
Very good
#28 of 221
Strong evidence · 16 sources
Water 14–15 °C (57–59 °F)
7. ATW Grafman Middle Distance Triathlon
Overall score 4.0Very goodStrong evidence · 16 sourcesTop 13%#28 of 221 overall
Grafham, United Kingdom · Next race 6 Jun 2027
Racers loveClear, shallow reservoir swim with a sandy beach start and an Australian exit
Watch outCold water around 14.5 °C (58 °F) and exposed to wind; the 2026 swim was choppy into a headwind
“Definately worth a day out.” RaceCheck: Rob E.
Water
14–15 °C (57–59 °F)
Field
about 300
Best
Race 4.4
Weakest
Bike 2.7
Not a standard 70.3
8. Sandman Legend (Newborough, Anglesey)
Newborough, United Kingdom
Next race 26 Sep 2027
Overall score 3.9
Very good
#36 of 221
Moderate evidence · 8 sources
8. Sandman Legend (Newborough, Anglesey)
Overall score 3.9Very goodModerate evidence · 8 sourcesTop 16%#36 of 221 overall
Newborough, United Kingdom · Next race 26 Sep 2027
Not a standard 70.3 · 1.9 / 93 / 20 km
Racers loveSea swim from Llanddwyn beach with Snowdonia as a backdrop
Watch outSea swim can be rough and tidal; sighting the exit matters
Best
Race 4.2
Weakest
Swim 3.3
9. IRONMAN 70.3 Weymouth
Weymouth, United Kingdom
Next race 12 Sep 2027
Overall score 3.9
Very good
#43 of 221
Moderate evidence · 8 sources
Water 16–18 °C (61–64 °F)
9. IRONMAN 70.3 Weymouth
Overall score 3.9Very goodModerate evidence · 8 sourcesTop 18%#43 of 221 overall
Weymouth, United Kingdom · IRONMAN · Next race 12 Sep 2027
Racers loveVoted most recommended race and best swim in EMEA in the 2024 athlete survey
Watch outSources disagree on bike climbing: about 800-1,400 m (2,600-4,600 ft)
“an amazing time and a weekend I will remember” IRONMAN Athletes' Choice Awards
Water
16–18 °C (61–64 °F)
Air
8–21 °C (46–70 °F)
Field
about 2,800
Best
Run 4.1
Weakest
Stay and travel 2.8
Not a standard 70.3
10. Roadford Lake Triathlon (Half Ironman)
Broadwoodwidger, United Kingdom
Next race 16 May 2027
Overall score 3.9
Very good
#48 of 221
Strong evidence · 10 sources
10. Roadford Lake Triathlon (Half Ironman)
Overall score 3.9Very goodStrong evidence · 10 sourcesTop 22%#48 of 221 overall
Broadwoodwidger, United Kingdom · Next race 16 May 2027
Not a standard 70.3 · 1.9 / 92 / 20 km
Racers loveLakeside base with Dartmoor views, easy parking and a friendly low-key atmosphere
Watch outHilly bike of about 92 km (57 mi) and a hard-to-judge run
Best
Race 4.5
Weakest
Bike 2.5
11. Outlaw Half Holkham
Holkham, United Kingdom
Next race 4 Jul 2027
Overall score 3.8
Very good
#53 of 221
Moderate evidence · 6 sources
Bike climb 645 m (2,120 ft)
11. Outlaw Half Holkham
Overall score 3.8Very goodModerate evidence · 6 sourcesTop 24%#53 of 221 overall
Holkham, United Kingdom · Next race 4 Jul 2027
Racers loveStart and finish in front of Holkham Hall with an orange-carpet finish
Watch outMurky, weedy lake
“an absolutely incredible venue” John Levison, Tri247: Outlaw Half Holkham delivers (2017)
Bike climb
645 m (2,120 ft)
Field
about 1,500
Best
Conditions 4.4
Weakest
Bike 2.3
Not a standard 70.3
12. Cowman Triathlon (Middle Distance)
Olney (Emberton Country Park), United Kingdom
Next race 1 Aug 2027
Overall score 3.8
Very good
#60 of 221
Moderate evidence · 9 sources
12. Cowman Triathlon (Middle Distance)
Overall score 3.8Very goodModerate evidence · 9 sourcesTop 28%#60 of 221 overall
Olney (Emberton Country Park), United Kingdom · Next race 1 Aug 2027
Not a standard 70.3 · 1.9 / 92 / 21.1 km
Racers loveCountry park HQ with parking, camping and a spectator-friendly four-lap run
Watch outWeedy, murky lake water and a swim briefing that confused some entrants in 2022
“I'm very happy with this race and will be doing it again” RaceCheck: Matt B.
Best
Stay and travel 4.3
Weakest
Bike 2.8
13. The Gauntlet (Hever Castle Half-Iron)
Hever, United Kingdom
Last race 27 Sep 2026
Overall score 3.7
Very good
#67 of 221
Moderate evidence · 7 sources
Water 16–19 °C (61–66 °F)
13. The Gauntlet (Hever Castle Half-Iron)
Overall score 3.7Very goodModerate evidence · 7 sourcesTop 31%#67 of 221 overall
Hever, United Kingdom · Last race 27 Sep 2026
Racers loveRace beneath Hever Castle with a large festival village
Watch outAbout 1,450 m (4,760 ft) of bike climbing over 90 km (56 mi); expect a slow day
“The course is not flat. Anywhere.” the5krunner: Hever Gauntlet race report 2016
Water
16–19 °C (61–66 °F)
Air
12–20 °C (54–68 °F)
Bike climb
1,450 m (4,760 ft)
Field
about 380
Best
Conditions 4.0
Weakest
Stay and travel 3.0
14. Outlaw Half Nottingham
Nottingham (Holme Pierrepont, National Water Sports Centre), United Kingdom
Next race 23 May 2027
Overall score 3.7
Very good
#70 of 221
Moderate evidence · 5 sources
Water 15 °C (59 °F)
14. Outlaw Half Nottingham
Overall score 3.7Very goodModerate evidence · 5 sourcesTop 32%#70 of 221 overall
Nottingham (Holme Pierrepont, National Water Sports Centre), United Kingdom · Next race 23 May 2027
Racers loveFast, flat-reputation course; the 2019 record is 3:51:44
Watch outLake water about 15 °C (59 °F) in 2019, with poor visibility reported in 2018
“Well organised fast 70.3, highly recommended.” RaceCheck (Paul C.)
Water
15 °C (59 °F)
Field
about 1,500
Best
Race 4.5
Weakest
Bike 2.7
Not a standard 70.3
15. Wimbleball 70.3 (Wimbleball Sports Festival)
Brompton Regis (Wimbleball Lake), United Kingdom
Next race 29 Aug 2027
Overall score 3.7
Very good
#72 of 221
Moderate evidence · 9 sources
15. Wimbleball 70.3 (Wimbleball Sports Festival)
Overall score 3.7Very goodModerate evidence · 9 sourcesTop 33%#72 of 221 overall
Brompton Regis (Wimbleball Lake), United Kingdom · Next race 29 Aug 2027
Not a standard 70.3 · 1.9 / 93 / 21 km
Racers loveWimbleball Lake: a clean, scenic reservoir swim with a venue history that stretches back to IRONMAN 70.3…
Watch outVery hilly: the 2018 route had over 5,000 ft (1,520 m (4,990 ft)) of ascent in 56 miles (90 km (55.9 mi))
Best
Swim 4.4
Weakest
Run 2.8
Not a standard 70.3
16. Slateman Legend (70.3 distance)
Llanberis, United Kingdom
Next race 13 Jun 2027
Overall score 3.6
Very good
#85 of 221
Moderate evidence · 5 sources
Bike climb 1,363 m (4,470 ft)
16. Slateman Legend (70.3 distance)
Overall score 3.6Very goodModerate evidence · 5 sourcesTop 39%#85 of 221 overall
Llanberis, United Kingdom · Next race 13 Jun 2027
Not a standard 70.3 · 1.9 / 92.6 / 23.1 km
Racers loveBike over Pen y Pass and the Llanberis and Nant Gwynant passes, rated spectacular
Watch outBike distance is 92.6 km (57.5 mi) on one page and 95.6 km (59.4 mi) on the organiser's 2026 page
“brutal and beautiful” Tri247 - Paul Hayward on the Slateman
Bike climb
1,363 m (4,470 ft)
Best
Race 3.6
Weakest
Stay and travel 2.9
17. The Gauntlet at Belvoir Castle
Belvoir (Grantham), United Kingdom
Next race 18 Jul 2027
Overall score 3.5
Very good
#90 of 221
Strong evidence · 12 sources
17. The Gauntlet at Belvoir Castle
Overall score 3.5Very goodStrong evidence · 12 sourcesTop 41%#90 of 221 overall
Belvoir (Grantham), United Kingdom · Next race 18 Jul 2027
Racers loveFast, mostly flat 90 km (56 mi) bike on quiet roads with good surfaces for the UK
Watch outShallow, weedy pond with four laps and many turns; congestion at buoys in 2024
Best
Conditions 3.9
Weakest
Run 2.9
Not a standard 70.3
18. Plymouth Triathlon Middle Distance (Mount Edgcumbe)
Cremyll (Plymouth), United Kingdom
Next race 13 Jun 2027
Overall score 3.1
Good
#158 of 221
Moderate evidence · 9 sources
Bike climb 1,385 m (4,540 ft)
18. Plymouth Triathlon Middle Distance (Mount Edgcumbe)
Overall score 3.1GoodModerate evidence · 9 sourcesBottom 30%#158 of 221 overall
Cremyll (Plymouth), United Kingdom · Next race 13 Jun 2027
Not a standard 70.3 · 1.9 / 90 / 20 km
Racers loveSheltered Plymouth Sound swim with Mount Edgcumbe estate as base
Watch outHilly bike: about 1,385 m (4,545 ft) of ascent over 90 km (56 mi)
Bike climb
1,385 m (4,540 ft)
Best
Conditions 3.9
Weakest
Bike 2.1
Not a standard 70.3
19. The Vitruvian Triathlon (Rutland Water middle distance)
Whitwell, Rutland Water (Oakham), United Kingdom
Last race 13 Sep 2026
Overall score 3.1
Good
#159 of 221
Strong evidence · 10 sources
19. The Vitruvian Triathlon (Rutland Water middle distance)
Overall score 3.1GoodStrong evidence · 10 sourcesBottom 30%#159 of 221 overall
Whitwell, Rutland Water (Oakham), United Kingdom · Last race 13 Sep 2026
Not a standard 70.3 · 1.9 / 89 / 21 km
Racers loveSheltered two-lap creek swim, 1.9 km (1.2 mi)
Watch outWind on exposed reservoir roads: the second bike lap was about 10 minutes slower in 2014
“biblical conditions” Mid Sussex Triathlon Club (Matt Critchley)
Field
about 800
Best
Swim 3.6
Weakest
Bike 1.2
20. The Northumbrian (Half Iron Distance)
Kielder, United Kingdom
Last race 28 Jun 2026
Overall score 3.0
Good
#172 of 221
Thin evidence · 3 sources
20. The Northumbrian (Half Iron Distance)
Overall score 3.0GoodThin evidence · 3 sources#172 of 221 overall
Kielder, United Kingdom · Last race 28 Jun 2026
Racers loveSwim in Kielder Water, bike across the Scottish border, run through Kielder Forest
Watch outRemote location and a long drive from Newcastle
“the heat was punishing” Claremont Road Runners member, Claremont Road Runners: The Northumbrian 29…
Best
Conditions 3.5
Weakest
Stay and travel 2.2
21. IRONMAN 70.3 Bolton
Bolton, United Kingdom
Next race 6 Jun 2027
Overall score 2.9
Good
#180 of 221
Moderate evidence · 7 sources
Water 14–19 °C (57–66 °F)
21. IRONMAN 70.3 Bolton
Overall score 2.9GoodModerate evidence · 7 sourcesBottom 19%#180 of 221 overall
Bolton, United Kingdom · IRONMAN · Next race 6 Jun 2027
Racers loveBig crowds on Chorley New Road and a finish at Bolton Town Hall
Watch outHilly bike of 757-840 m (2,484-2,756 ft) with exposed moorland crosswinds
Water
14–19 °C (57–66 °F)
Air
9–18 °C (48–64 °F)
Bike climb
840 m (2,760 ft)
Best
Run 3.8
Weakest
Conditions 2.7

About these ratings

Races are ranked by an overall score out of 5, built from racer reviews and race reports, on the race itself, swim, bike, run, conditions and travel. 5 is always the better end. How we rate

70.3 course: 1.9 km (1.2 mi) swim, 90 km (56 mi) bike, 21.1 km (13.1 mi) run.

Reports on 70.3 races are scarcer, so 1 of 21 scores are thin evidence: fewer than 5 sources each (dashed score, marked provisional). Show only races with 5+ sources. 9 races run a non-standard course and are flagged.

178 racer reviews and race reports.

Browse all 21 races, A to Z

Training for one of these? Moku Coach builds your plan around race day.