Ardnacrusha Locks

Closed from 1 October 2026 to 31 March 2027 for ESB maintenance on the gate equipment (Marine Notice 106/2026); ESB says it will post progress updates before the reopening.

This is the only way between Lough Derg and Limerick: two chambers in a staircase with a combined fall of up to about 34 m, said to be the deepest lock in Ireland and Britain. ESB runs it, not Waterways Ireland. Book with the lock-keeper (+353 87 997 0131 or +353 61 344 515) before setting off. The chamber is about 32 m by 6 m, room for two mid-sized cruisers. Allow about an hour in the lock and a long wait between lockings; you hold on to cables or hooks in the high walls. Headroom under the gates changes with the headrace level and the tide, so tell the keeper your air draft.