The volunteer crew launched their Atlantic 85 lifeboat Louis Simson at 11.30am following a call to Dublin Coast Guard from a concerned member of the public about a swimmer in the water off Red Island headland.
The lifeboat, with Joe May at the helm and crewed by David Knight, AJ Hughes and Stephen Crowley, launched and proceeded directly to the area indicated by the coastguard.
Arriving on scene, it was discovered there was a local swimming group ashore after returning from a swim. After speaking to the group, the volunteer crew were assured that everyone was accounted for.
The lifeboat performed a precautionary sweep of the area before being stood down and returning to station.
The Irish Coast Guard helicopter Rescue 116 was also on scene and carried out a search before returning to base.
Speaking after the callout, Gerry Canning, volunteer lifeboat press officer for Skerries RNLI, said: "Thankfully in this case our assistance wasn’t required.
"However, the member of public had good intentions and we would always advise people to dial 999 and ask for the coastguard if they think they see someone in difficulty at sea."