Swimming

A swim off the boat on a warm evening, or a dip at a lakeside beach, is one of the joys of a summer trip. Inland water in Ireland is also cold, can be deep right off the shore, and is shared with boats. A few rules keep a swim a good memory.

The best places: official bathing waters

Only four official bathing waters lie on the navigations, all of them on Lough Derg: the Bathing Place at Portumna, Mountshannon, Ballycuggeran near Killaloe, and Dromineer. The first three hold a Blue Flag for 2026 and were rated Excellent for 2025; Dromineer was rated Good (beaches.ie, Blue Flag list 2026). The official bathing season runs from 1 June to 15 September, when the water is tested and lifeguards are on duty at set times. Check beaches.ie for the latest water-quality alerts before you go in.

Elsewhere on the Shannon, the Erne, the canals and the Barrow there is no designated bathing water. That does not mean swimming is forbidden, only that nobody tests the water or watches over it.

Where you must not swim

Waterways Ireland is clear about this (Special Marine Notice 1/2026):

• Not in the navigation channel, where boats pass, and especially not near bridges and weirs.
• Not in or near locks, on the canals or the rivers. The water moves violently when a lock fills or empties.
• Swimming in the canals is allowed in principle, but some hire companies forbid it in their contracts (Emerald Star does, for example: FAQ). Check yours, and ask at the base where swimming is safe.

Also stay out of the water near harbour entrances, slipways and marinas, and anywhere you see a strong current, such as below a weir or between Ardnacrusha and Limerick.

Swimming from the boat

1. Moor or anchor first, well out of the channel, and switch the engine off. A turning propeller is the worst danger there is.
2. Put the swim ladder down before anyone goes in, and check you can climb back up it. Getting out is harder than getting in.
3. Someone stays on board and watches, with a lifebuoy and a rope ready.
4. Don't dive or jump unless you know the depth: lake bottoms are uneven and can hide rocks and old timber.
5. Stay close to the boat or the shore; distances over water are longer than they look.

Lifejacket law allows you to take your lifejacket off to swim from a boat that is not moving (S.I. 921/2005). Children who are not strong swimmers can swim in theirs.

Cold water

Even in July the lakes are much colder than a pool, and colder still in spring and autumn. Sudden cold makes you gasp and breathe fast, and within two or three minutes it can cause panic and drowning (Water Safety Ireland). Get in slowly, let your breathing settle before you swim, and get out before you feel cold.

Good habits

• Never swim alone, and never after drinking.
• Wear a bright swim cap or tow float so boats can see you (Water Safety Ireland).
• Skip the swim after heavy rain, when rivers carry run-off, and wherever the water looks green and scummy in hot weather: algae blooms can make people and dogs ill.
• Shower afterwards and keep cuts covered.
• Watch the weather: wind makes waves, and swimmers in waves are hard to see.

Swim events

Organised open-water swims take place on the waterways each summer, such as the Gaelforce Great Lake Swim at Portumna and the Great River Swim at Lanesborough. On those days parts of the water may be closed to boats: watch for marine notices and see our events.