Merrion Strand in Dublin will be the first beach in the country shut to swimmers under water quality law.
It's after a new bathing water report from the Environmental Protection Agency found it to be of poor standard for the fifth successive year.
The ban will take effect from June 1st, with signs set to be put up warning people to keep out of the water.
In total, 147 water bodies were assessed in the report, with 140 meeting the minimum required standard.
Most Wicklow Residents Unprepared for Retirement, PTSB Research Finds
Wicklow Property Prices Jump €25,000 In A Year As Supply Tightens
West Wicklow To Receive Major Fire Service Investment Under National Capital Programme
Tánaiste Announces €40 Million Investment For Blessington Housing Development
Major Easter Rail Works Set to Disrupt Wicklow Commuters