Trá an Dóilín, An Ceathrú Rua is classified as achieving Excellent Water Quality in 2025 based on the assessment of bacteriological results for the period 2022 to 2025. Trá an Dóilín, An Ceathrú Rua has achieved an Excellent Water Quality rating for the four consecutive years 2022 to 2025. Annual water quality ratings are generally calculated using monitoring results over a four-year period and are assessed against stringent bacterial limits to protect bather health.

Trá an Dóilín is an unusual beach formed from a plethora of dead fragments of "maerl", a twig-like calcareous seaweed. This type of beach material is washed up at only a few locations in Ireland. It is an exposed beach which is subject to very strong wave action at times. The bathing area comprises a number of different habitats in close proximity to the beach including rocky outcrops, rock pools, off shore reefs and a fresh water lagoon. These different habitats support a variety of different plant, animal and bird species. It is a popular beach for snorkelling and diving.