Best Olympic-distance triathlons in Ireland
4 rated races, ranked by an overall score built from racer reviews and race reports. How we score
4 races
By the numbers- Overall score 3.4Good#77 of 164
Strong evidence · 4 sources + 224 runner ratings
Water 13–16 °C (55–61 °F)
1. Lough Cutra Castle Triathlon (Castle Series)
Overall score 3.4GoodStrong evidence · 4 sources + 224 runner ratingsTop 47%#77 of 164 overallGort, Ireland · Next race 29 May 2027
1.5 / 44 / 10 kmRacers loveSwim in a private lake below the castle; Racecheck rates water quality 4.78 of 5.
Watch outLake is 13 to 16 °C (55 to 61 °F), even in late May.
“what an absolutely stunning setting” Racecheck reviewers, Racecheck: Lough Cutra Castle Triathlon Series
- Water
- 13–16 °C (55–61 °F)
- Air
- 9–17 °C (48–63 °F)
- Field
- about 2,000
- Best
- Race 3.6
- Weakest
- Run 2.6
Overall score 3.3Good#93 of 164Thin evidence · 3 sources
2. Dublin City Triathlon
Overall score 3.3GoodThin evidence · 3 sources#93 of 164 overallDublin, Ireland · Last race 22 Aug 2026
Racers lovePark roads are closed to traffic for the bike
Watch outRiver water quality varies; a 2019 sewage discharge hit the nearby Liffey Swim
- Air
- 12–20 °C (54–68 °F)
- Field
- about 900
- Best
- Bike 4.4
- Weakest
- Race 2.8
Overall score 3.1Good#130 of 164Thin evidence · 2 sources
Water 13–16 °C (55–61 °F)
3. Westport Triathlon
Overall score 3.1GoodThin evidence · 2 sources#130 of 164 overallWestport, Ireland · Last race 15 Aug 2026
Racers loveSea swim in Clew Bay with Croagh Patrick as the backdrop.
Watch outThe sea was 13.9 °C (57 °F) in 2019, so a wetsuit is essential.
- Water
- 13–16 °C (55–61 °F)
- Air
- 12–19 °C (54–66 °F)
- Field
- about 400
- Best
- Run 3.4
- Weakest
- Swim 2.8
Overall score 3.0Good#140 of 164Moderate evidence · 4 sources
Water 13–16 °C (55–61 °F)
4. Base2Race Harbourman Triathlon
Overall score 3.0GoodModerate evidence · 4 sourcesBottom 16%#140 of 164 overallWicklow Town, Ireland · Last race 28 Jun 2026
Racers love1,500 m (0.93 mi) swim in clear water outside the harbour walls
Watch outOlympic only, with no sprint, so it suits experienced athletes more than first-timers
“hilly Wicklow roads” Triathlon Ireland: Harbourman 2022
- Water
- 13–16 °C (55–61 °F)
- Air
- 11–20 °C (52–68 °F)
- Field
- about 500
- Best
- Stay and travel 3.9
- Weakest
- Race 2.6
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
Olympic course: 1.5 km (0.9 mi) swim, 40 km (24.9 mi) bike, 10 km (6.2 mi) run.
Reports on Olympic-distance races are scarcer, so 2 of 4 scores are thin evidence: fewer than 4 sources each (dashed score, marked provisional). Show only races with 4+ sources. 1 of these races set their own distances, and each race page lists the real course.
13 racer reviews and race reports.
Browse all 4 races, A to Z
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