Wicklow County Council has issued a "do not swim" notice for Brittas Bay South due to the poor microbiological quality of the water.
Water test results revealed high levels of Ecoli and intestinal enterococci.
Further tests have been carried out and the results are expected on Saturday.
Meanwhile, a precautionary notice for Bray North and South Promenade has been removed.
Fingal County Council earlier lifted bathing restrictions on some designated bathing areas in north Co Dublin, following the testing of samples taken on Tuesday.
Advisory notices have been removed from Balcarrick Beach in Donabate, Malahide Beach, Portmarnock Beach, Burrow Beach in Sutton, Claremont Beach, and Hampton Cove in Balbriggan.
However, bathing continues to be prohibited due to poor water quality at Balbriggan Front Beach, Skerries South Beach, Loughshinny Beach, Rush South Beach, Portrane Beach (The Burrow) and Rush North Beach.
Initial advisory notices were placed in all designated bathing areas under the jurisdiction of Fingal County Council following heavy rainfall over the bank holiday weekend.
Repeat samples were taken today, and final results will be available on Saturday.