Dublin City Triathlon
Dublin, Ireland · August · Independent (Piranha Triathlon Club, Triathlon Ireland National Series)
Course: 0.8 km (0.5 mi) swim, 23 km (14.3 mi) bike, 5 km (3.1 mi) run. 2026: 750 m / 23 km / 5 km (0.47 / 14.3 / 3.1 mi); 2017-2019 bike was 20 km (12.4 mi)
Why people love it
- Park roads are closed to traffic for the bike
- Rolling start in the sheltered upper Liffey, glassy in 2026
- Swim, transition and finish share one base at the Garda Boat Club
- Try-a-Tri option alongside the sprint
- Dublin Airport is about 12 km (7.5 mi) away, with buses and trains
Watch out for
- River water quality varies; a 2019 sewage discharge hit the nearby Liffey Swim
- Course and distances change by year: bike 20 km (12.4 mi) before, 23 km (14.3 mi) in 2026
- Irish weather ranges from damp to blustery; the 2019 race was windy
- Few athletes have written about the race, and the 2026 Olympic race is unconfirmed
- Dublin hotels are pricey in summer; parking details are unconfirmed
Race
How racers feel about it, how well it is run, and how it treats a first timer. Counts for 30% of the overall score.
Toughness: Moderate
- Racer satisfactionLoved3.6
Results reports and a 2017 political quote are positive, but no athlete has written a full race report. · Low confidence
- OrganizationWell run3.7
The Triathlon Ireland national series round ran with rolling starts and no reported problems, though few athletes have commented. · Low confidence
- First timer friendlyFriendly3.9
Sprint with a rolling start and a Try-a-Tri alongside. · Low confidence
Course traits, not part of the score
- PR potentialFast3.5
A 20 to 23 km (12.4 to 14.3 mi) closed-road bike and a fast run. · Low confidence
Swim
Wetsuit odds, water temperature, calm, and the experience of the start. Counts for 16% of the overall score.
- Wetsuit legalUsually4.2
Triathlon Ireland follows World Triathlon (no wetsuits above 24.6 °C (76 °F) / 76.3 °F). August river water is almost certainly cooler. · Low confidence
- Water temperatureAcceptable3.3
No temperature published. A 2017 racer called it remarkably warm; Irish August rivers are typically 16 to 19 °C (61 to 66 °F). · Low confidence
- Calm waterMostly calm4.3
Sheltered upper Liffey, glassy in 2026, with a rolling start to ease congestion. · Low confidence
- Swim easeEasy4.1
750 m (0.47 mi), one lap, rolling start. · Medium confidence
- Swim experienceFine3.1
Urban river beside a rowing club. A 2019 sewage discharge affected the nearby Liffey Swim, though the 2017 race swim was called clean. · Low confidence
- Swim supportGood3.7
Rolling start from a rowing-club base; no safety details are published. · Low confidence
Bike
Road surface, closures, scenery and wind. Counts for 18% of the overall score.
- Road surfaceGood3.7
Park roads; no complaints found. · Low confidence
- Road closuresFully closed4.5
Park roads have been closed in every report since 2009. · Medium confidence
- Bike sceneryBeautiful3.7
Large deer park with parkland views. · Low confidence
- WindSome wind3.3
Trees give shelter, but 2019 was blustery. · Low confidence
Course traits, not part of the score
- Bike speedFast3.8
Closed Phoenix Park roads; the 2018 sprint winner rode 20 km (12.4 mi) in 29:41. · Medium confidence
- Bike flatnessMostly flat3.8
Three short laps in 2026; no elevation published. · Low confidence
- Bike simplicitySome technical parts3.0
A three-lap circuit with turnarounds, described as technical in 2025. · Medium confidence
Run
Crowds, aid stations, conditions underfoot and scenery. Counts for 13% of the overall score.
- Crowd supportDecent3.3
Laps along Chapelizod Road and the park allow spectators, but no one describes the atmosphere. · Low confidence
- Aid stationsStandard3.3
No details published on aid stations. · Low confidence
- Run sceneryBeautiful3.5
Park and riverside. · Low confidence
- Run conditionsEasy3.7
Three laps over 5 km (3.1 mi). · Low confidence
Course traits, not part of the score
- Run flatnessMostly flat3.7
Three flat-ish laps on Chapelizod Road in 2026. · Low confidence
Conditions
Air temperature, how predictable the weather is, setting, and spectating. Counts for 13% of the overall score.
- Air temperaturePleasant4.3
Late August in Dublin is typically 12 to 20 °C (54 to 68 °F). · Medium confidence
- Weather reliabilityVariable2.9
Damp start in 2018, blustery in 2019, glassy and calm in 2026. · Medium confidence
- Venue beautyLovely3.9
Phoenix Park and the Liffey, a large green space in the city. · Medium confidence
- Spectator friendlyEasy3.8
Multi-lap bike and run in one park area. · Low confidence
Course traits, not part of the score
- Low altitudeSea level5.0
The park sits about 20 to 90 m (65 to 295 ft) above sea level. · High confidence
Stay and travel
Hotels, walkability, getting there, and the town around the race. Counts for 10% of the overall score.
- Hotel availabilityGood3.8
Large city; busy in August but plentiful. · Low confidence
- Hotel valueNormal2.8
Dublin hotels are pricey, especially in summer. · Low confidence
- WalkabilitySome driving3.3
Swim, transition and finish share the Garda Boat Club base; parking is unconfirmed. · Low confidence
- Travel easeVery easy4.6
Dublin Airport is about 12 km (7.5 mi) from Phoenix Park, with city buses and trains. · High confidence
- LogisticsSimple3.9
Swim, transition, bike and run share one venue, with a rolling start. · Low confidence
- Town and foodGreat4.6
Capital city with abundant food and lodging. · Medium confidence
Key facts
- Location
- Dublin, Leinster, Ireland
- Typical month
- August
- Latest or next date
- 22 August 2026
- Organiser
- Independent (Piranha Triathlon Club, Triathlon Ireland National Series)
- Field size
- About 900 athletes
- Distances (non-standard)
- 0.8 km (0.5 mi) swim, 23 km (14.3 mi) bike, 5 km (3.1 mi) run
- Swim venue
- Upper River Liffey from the Garda Boat Club, Chapelizod Road (river)
- Wetsuit
- Legal
- Swim start
- rolling
- Swim laps
- 1
- Bike laps
- 3
- Key climbs
- Kyber Pass, about 1 km (0.6 mi), used in 2018
- Run laps
- 3
- Run shade
- park trees
- Air temperature
- 12–20 °C (54–68 °F)
- Humidity
- moderate
- Altitude
- 30 m (98 ft)
- Nearest airport
- Dublin (DUB), 12 km (7 mi) away
- Where to stay
- Stoneybatter, Chapelizod, city centre
- Booking
- City hotels near Phoenix Park, Heuston and the city centre; Dublin is pricey in summer.
What racers and reviewers say
- Triathlon Ireland: RDJ Dublin City Triathlon 2026Raced 2026 · article · Positive
National Series round 14 hosted by Piranha TC. 750 m (0.47 mi) swim in the Liffey from the Garda Boat Club in calm, glassy water; 23 km (14.3 mi) bike in three laps via Chapelizod Road and Phoenix Park; 5 km (3.1 mi) three-lap run. Perfect late-August morning and no problems reported.
- Triathlon Ireland: Dublin City Triathlon 2025 gallery and race reportRaced 2025 · article · Positive
Round 13 of the national series with Sprint, Standard (Olympic), Aquabike, Try-a-Tri and a corporate relay offered. Bike and run described as technical in Phoenix Park; no incidents mentioned.
- Triathlon Ireland: national series at DCT 2019Raced 2019 · article · Positive
Age Group Sprint National Championships. Rolling start made the Liffey calmer for nearly 900 age-group athletes; 20 km (12.4 mi) bike; dry but blustery day after wet weather.
- Triathlon Ireland: BMW series at DCT 2018Raced 2018 · article · Positive
Damp start, then good conditions. 750 m (0.47 mi) rolling-start swim, two laps of a 20 km (12.4 mi) park bike with a 1 km (0.6 mi) Kyber Pass climb, a new 5.5 km (3.4 mi) run that also climbed it. 585 raced plus 78 in Try-a-Tri, many first-timers.
- Triathlon Ireland: Taoiseach races Dublin City TriathlonRaced 2017 · article · Positive
The then Taoiseach raced and called the Liffey remarkably warm and clean. Over 1,100 took part in 750 m (0.47 mi) swim, 20 km (12.4 mi) park bike and 5 km (3.1 mi) run.
“remarkably warm and clean”
Show 2 more
- 220 Triathlon: Dublin Tri introduces the Super SprintRaced 2009 · article · Positive
Preview of the 2009 edition: a newcomer-friendly Super Sprint (600 m (1,970 ft) / 0.37 mi, 16 km / 9.9 mi, 4 km / 2.5 mi) and standard Olympic (1,500 m / 0.93 mi, 40 km / 24.9 mi, 10 km / 6.2 mi). Bike on closed Phoenix Park roads, off-road run, upper Liffey swim by rowing clubs.
- Irish Times: Liffey Swim to go ahead despite poor water qualityRaced 2019 · article · Negative
Context only: council samples in 2019 after a sewage discharge near Knockmaroon were far above bathing limits on the Liffey Swim reach; the river is not a designated bathing water. A reminder that river quality can vary by year.
Raced Dublin City Triathlon? Your notes on the course, conditions and logistics help the next athlete decide.
Sources
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