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sport · Sunday 12 July 2026 · 8:00am 
Dublin Bay to Dun Laoghaire Swim
At Dublin Bay · Dublin Bay to Dun Laoghaire, Co. Dublin
At Dublin Bay · Dublin Bay to Dun Laoghaire, Co. Dublin
A 5km sea swim along the Dublin coastline, finishing at one of Ireland’s most recognisable harbours, is a proper challenge for any serious open water swimmer. The Dublin Bay to Dún Laoghaire Swim, organised by the Irish Open Water Swimming Association, takes participants along the southern arc of Dublin Bay before reaching the granite piers of Dún Laoghaire. The 8am start means swimmers are out on the water at its calmest, with the morning light on the bay and the Wicklow hills visible to the south. It suits experienced open water swimmers who are comfortable in the sea and want a genuine distance event rather than a leisure dip.
The swim covers approximately 5km of open coastal water, which puts it firmly in long-distance territory. At that distance you will feel the tide, the chop, and the gradual pull of the current - conditions that change from week to week on Dublin Bay. Professional safety support is in place throughout, with a chase boat and qualified lifeguards tracking the field. The finish at Dún Laoghaire pier is a well-earned arrival: the harbour walls provide shelter and there is usually a crowd watching from the pier. Wetsuits are optional, which is common for competitive open water events in Ireland, though the sea temperature in July typically sits between 14 and 17 degrees Celsius - a wetsuit makes a long swim more sustainable for most people. Experienced open water swimmers are recommended, not just advised: 5km of coastal sea swimming in variable conditions is not an event for beginners.
Dún Laoghaire is about 12km south of Dublin city centre, easily reached by DART from Connolly or Pearse stations - the journey takes around 25 minutes and drops you at Dún Laoghaire station, a short walk from the harbour. By road, the N11 or coast road (R118) brings you in from the city. Parking near the harbour can be tight on summer mornings; the multi-storey at the Lexicon library or street parking on the seafront roads are the main options. Check the event instructions for where the finish and registration area are set up - for an event with a point-to-point route, there will be specific transport or logistics advice from the organisers.
Dún Laoghaire has the East and West Piers for a post-swim walk, plenty of cafes for a well-deserved breakfast, and the People’s Park if you want to sit and recover in the sun. The town has been a sea-swimming base for Dubliners for generations, and on a July morning the atmosphere around the harbour is hard to beat. There is more to see in Dún Laoghaire and across Co. Dublin.
Heading to Dublin Bay in Dún Laoghaire? Dublin has plenty more to see. Read the Dún Laoghaire area guide, find what else is on, and explore the towns and villages nearby.