More than 90% of Ireland's bathing waters have been classed as either excellent or of a very high standard, according to the latest bathing Water Quality Report from the Environmental Protection Agency.
However, six coastal locations, including Merrion Strand in Dublin, failed the minimum standard and the public will be advised not to swim there this summer.
The EPA said it is extremely encouraging that there was very little change in the number of bathing waters achieving its "excellent" classification for 2015.
Overall, the agency monitored 137 official bathing locations but only six were classified as "poor".
Four of these: Youghal in Co Cork, Duncannon in Co Wexford, Rush South Beach in Dublin and Ballyloughane in Co Galway were first classified as poor in 2014 but showed noticeable improvements in quality in 2015.
Two beaches, Merrion Strand and Loughshinny, both in Dublin, were newly classified as of poor quality and the public will be advised not to bathe there this summer.
However a senior scientist with the EPA, Peter Webster, said that the six areas classed as "poor water" in the report remain safe to swim in.
Speaking on RTÉ’s Morning Ireland, Mr Webster said that the areas did not reach minimum microbiological standards set down by the EU, but those standards are now twice as strict as they used to be.
He added that while local authorities are legally obliged to let the public know when waters do not meet the standards, that does not mean it is unsafe to swim in.
"All of the local authorities have to advise the public that the water quality has been classed as poor. And that means that from time to time it's subject to potential pollution," Mr Webster said.
"It doesn't mean that it's a problem now, doesn't mean that it's unsafe now. In fact in 2015 four of those poor waters actually showed very, very good performance."
