Bathing waters in Rhyl, Prestatyn, Kinmel Bay and Pensarn have been given an overall clean bill of health.
Data by Natural Resources Wales show 99 per cent of Welsh bathing water has complied with tough European standards.
The Bathing Waters in Wales results for 2017 rates 80 of Wales’ 104 bathing areas as “excellent”.
At Marine Lake and Rhyl East, water quality was classed as “good”, while at Rhyl beach (Clwyd Estuary to Splash Point), a sample taken from opposite Rhyl SeaQuarium measured waters as “sufficient” – the same outcome as 2016 and 2015.
At Prestatyn beach, water quality was described as “excellent”.
Waters at Kinmel Bay (Sandy Cove) were deemed as “good”. Last year the quality was marked as “excellent” and the same again in 2015.
Abergele Pensarn waters, opposite Pensarn train station, were measured as “good”.
A total of 103 of 104 bathing waters in Wales were compliant with the European standards, making Welsh bathing water among the best in Europe.
Lesley Griffiths, Cabinet Secretary for Environment and Rural Affairs, said: “Wales has some of the most beautiful coastline, which attracts thousands of visitors every year.
“Maintaining our bathing waters to these high standards is essential if we are to continue selling Wales as a holiday destination.
“But this is not just about those visiting Wales. A healthy environment helps to sustain our economy and improves our quality of life. With clean bathing waters, our coast and natural environment will continue to provide huge benefits to people across Wales – from rural West Wales to more urban South Wales.”
Kevin Ingram, interim chief executive for Natural Resources Wales, added: “Welsh bathing waters are considered to be some of the best in Europe and once again our beaches have maintained their position with 80 out of 104 beaches achieving excellent status and 99 per cent rated as sufficient or higher.
“This is especially pleasing as the wet summer had a direct impact on water quality across the UK.”