Three men were recovered from the water.
The bodies of the deceased were found near the South Kerry coast.
It's believed the men were on a boat together before the incident which took the lives of one man in his 50s and two men in their 30s.
Gerard O'Flynn of Irish Coast Guard said the Gardaí were on hand to help the operation: "A full-scale search and rescue operation was mounted, involving the Coastguard helicopter based in Shannon, Valentia Lifeboat, local volunteer Coast Guard unit, and the operation was coordinated closely with An Garda Síochána."
"Shortly before seven o'clock, a body was recovered by the Coast Guard helicopter, and a few minutes later, two other bodies were sighted and were also recovered by the Coast Guard helicopter.All information indicates that three people were on board the boat, so sadly three lives were lost," he added.