A two hour search took place last night off the coast of Sandymount Strand in Dublin following reports of a person in the water.
Volunteers from Dun Laoghaire RNLI were involved in multi-agency search, which it says transpired to be a false alarm with good intent.
The Irish Coast Guard helicopter Rescue 116 from Dublin, Dun Laoghaire Coast Guard unit, the Irish Air Corps and the Gardaí were also tasked.
Weather conditions at sea were good making visibility ideal for searching.
No evidence was found, and the Coast Guard stood down the operation at 12am.
Speaking following the call out, Dun Laoghaire RNLI Helm Alan Keville, said: ‘We are always here to respond to any situation that may arise at sea and this one was no different.
"The report to the Irish Coast Guard by a member of the public was most definitely made in good faith we would like to commend them for doing the right thing."
He said the Dun Laoghaire RNLI wanted to "make sure no life was at risk as fast-moving tides and sandbanks have been a problem in this area in the past."