A popular bathing spot was sealed off by Gardai after a body was recovered from the waters in Dun Laoghaire on Tuesday evening.
The man in his 40's was rushed to St Vincent's Hospital but he was later pronounced dead.
A post mortem will take place in the coming days and investigations are ongoing.
A spokesperson for An Garda Siochana told Dublin Live: "Gardaí and emergency services attended the Dun Laoghaire beach yesterday evening Tuesday 17th August 2021.
"A male aged in his 40s was recovered from the water and taken to St Vincent’s Hospital where he was pronounced deceased.
"A post mortem will take place in due course.
"Investigations are ongoing."
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