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sport · Saturday 11 July 2026 · Various 
Gaelforce Great Lake Swim - Lough Derg, Mountshannon
At Mountshannon Harbour, Lough Derg · Mountshannon, Co. Clare
At Mountshannon Harbour, Lough Derg · Mountshannon, Co. Clare
Lough Derg is one of Ireland’s finest open water venues, and Mountshannon is one of the best spots on it - clear, freshwater, sheltered, with an International Blue Flag beach right beside the harbour. Gaelforce Events brings a proper swim event here every July, offering three distances so that a nervous first-timer and a seasoned triathlete can both line up on the same morning. If you have been thinking about trying open water swimming in a structured, supported environment, this is one of the most appealing places in the country to start.
The event runs across three distances: 750m, 2km and 3.9km. The longest option - 3.9km - is full Ironman swim distance, while the 750m is accessible for anyone with basic swim fitness. Both wetsuit and non-wetsuit swimmers are welcome across the distances, so there is no pressure on kit. Mountshannon Beach provides a sheltered, soft-bottomed entry on the western shore of Lough Derg, and the water quality here is consistently excellent - Clare County Council monitors it as a designated bathing area.
The event is the second in the Gaelforce Great Swim Trilogy, which takes in the River Shannon, Lough Derg, and the Killary Fjord in Connemara. Completing all three earns trilogy status. Wave times are staggered - check the Gaelforce website for the full schedule as the day is confirmed.
A festival atmosphere is part of what Gaelforce do: there is typically a post-swim gathering at the venue, so it is worth arriving early and staying a while. Participants must be aged 16 or over; 16-17 year olds need a signed parental consent form at registration.
Mountshannon is on the R352 in east Clare, roughly 30km south-east of Ennis and about 25km from Portumna. By road from Dublin, take the M7 and M18 toward Limerick then head north on the R352 - allow around two and a half hours. There is no direct public transport to Mountshannon on a weekend, so driving or car-sharing is the practical option. Parking in the village is limited; follow event signage on the day to designated overflow areas.
The harbour is worth a slow walk before or after your swim - cruisers moor here in summer, and Bushy Island sits just offshore with its early monastic ruins visible from the pier. There is more to see in Mountshannon and across Co. Clare.
Heading to Mountshannon Harbour, Lough Derg in Mountshannon? Clare has plenty more to see. Read the Mountshannon area guide, find what else is on, and explore the towns and villages nearby.