If you are planning a beach holiday on Anglesey, the quality of the water you and your family will be swimming in matters. The good news is that Trearddur Bay and the surrounding coastline consistently rank among the cleanest bathing waters in Wales. The team at Trearddur Bay Holiday Homes welcomes hundreds of families, couples and groups to the village every year, and the water quality is one of the reasons guests keep coming back.
Official Bathing Water Classifications for Trearddur Bay and Holy Island
Every year, Natural Resources Wales monitors bathing water quality at designated beaches across the country. Samples are taken at least eight times between May and September, testing for bacteria including intestinal enterococci and E. coli. The results are used to classify each beach as Excellent, Good, Sufficient or Poor under the Bathing Water Directive.
In the most recent 2025 classifications published by the Welsh Government, Trearddur Bay received a Good rating. Neighbouring Porth Dafarch – a popular cove for coasteering, kayaking and wild swimming just a mile up the coast – was classified as Excellent. These ratings are based on a rolling four-year dataset, meaning they reflect sustained water quality rather than a single season. For visitors staying in one of the holiday properties managed by Trearddur Bay Holiday Homes, both beaches are within easy walking or a very short drive.
Why Anglesey Has Some of the Cleanest Seas in Britain
Anglesey sits in the path of the prevailing Atlantic currents that sweep through the Irish Sea. The combination of strong tidal flow, relatively low coastal population density and the absence of heavy industry means the waters around Holy Island are exceptionally clean by UK standards. There are no major river estuaries discharging near Trearddur Bay, and the rocky coastline allows natural filtration of surface runoff before it reaches the sea.
The results across the wider island bear this out. In the same 2025 Welsh Government assessment, Rhosneigr, Aberffraw, Church Bay, Llanddwyn, Traeth Lligwy, Llanddona and St Davids at Benllech all received Excellent ratings. Anglesey is, by any measure, one of the best places in Wales for clean sea swimming. Guests of Trearddur Bay Holiday Homes are within a 30-minute drive of all of these beaches.
Blue Flag Status: What It Means and Why It Matters Less Than You Think
Trearddur Bay and Porth Dafarch were both awarded the Blue Flag in 2021, an international standard assessed against 32 criteria including water quality, environmental management, safety and facilities. However, the beach has not held the award since. This is not because the water quality has declined.
The Isle of Anglesey County Council, along with Gwynedd and Conwy councils, chose not to submit applications to Keep Wales Tidy for the Blue Flag programme in subsequent years. The reasons are administrative and budgetary, not environmental. The water quality at Trearddur Bay has remained consistently Good throughout this period, and the beach continues to be monitored under the statutory bathing water programme. In practical terms, a family swimming at Trearddur Bay in 2026 is swimming in water that meets the same rigorous standards it always has. The absence of a Blue Flag is a bureaucratic footnote, not a water quality concern.
Swimming, Paddleboarding and Watersports at Trearddur Bay
The beach itself is well suited to swimming at all stages of the tide. The main bay has a wide stretch of sand that slopes gently into the water, making it safe for children and confident swimmers alike. The rocky coves at either end of the bay offer calmer, more sheltered water on windier days. At low tide, the rock pools are a source of endless fascination for younger visitors.
Paddleboarding has become hugely popular at Trearddur Bay in recent years. The relatively sheltered bay offers flat water conditions on calm days, while the headlands provide interesting coastal routes for more experienced paddlers. Sea kayaking, coasteering and surfing are all available through local activity providers operating from Porth Dafarch. Properties managed by Trearddur Bay Holiday Homes along Ravenspoint Road and the coastal path are particularly well positioned for direct beach access.
Practical Information for Beach Days at Trearddur Bay
The main beach at Trearddur Bay has a car park operated by the Isle of Anglesey County Council, with pay-and-display charges in effect during the summer season. Arriving before 10am in peak weeks is advisable if you want a space close to the beach. There are public toilets at the beach, and the village has a convenience store for last-minute supplies. The Sea Shanty restaurant sits right on the seafront and is open for breakfasts, lunches and evening meals throughout the season.
Dogs are welcome on parts of Trearddur Bay beach year-round, though a seasonal dog ban area operates on the main bathing beach from 1 May to 30 September. During these months, dogs are banned from the central sandy area but are permitted on the surrounding rocky sections and smaller coves. Dogs must be kept on leads on the promenade at all times. The map below, produced by the Isle of Anglesey County Council, shows the exact boundaries of the restricted zone.
Outside of the summer restriction period, Trearddur Bay is a wonderful beach for dogs. If you are visiting with a four-legged companion, many of the properties managed by Trearddur Bay Holiday Homes are dog-friendly with secure gardens. The dog-friendly pubs on Anglesey are also well worth exploring after a day on the sand.
Stay Within Walking Distance of the Beach
Many of the properties in the Trearddur Bay Holiday Homes portfolio are a short walk from the water. Porth House, a premium three-bedroom home sleeping six from £1,250 per week, sits right on the coast with sea views from the balcony and its own sauna – ideal after a day in the sea. For families, Penmorfa sleeps nine from £995 per week and has a secure garden and open fire for those evenings when the children are exhausted from a full day on the sand.
Browse the full range of self-catering holiday properties or call the team at Trearddur Bay Holiday Homes directly on 01407 861 788 to discuss which property best suits your plans.
Frequently Asked Questions
Is the sea safe for swimming at Trearddur Bay?
Yes. The beach is classified as Good under the Welsh Government bathing water programme. Neighbouring Porth Dafarch holds an Excellent classification. Both are regularly tested between May and September.
Does Trearddur Bay have Blue Flag status?
The beach held the Blue Flag in 2021 but the local authority has not submitted applications since. This is an administrative decision, not a reflection of water quality. The bathing water classification has remained consistently Good.
Can I take my dog to Trearddur Bay beach?
Dogs are welcome outside of the summer restriction period (typically 1 May to 30 September). During summer, dogs are permitted on the rocky areas and smaller coves but not on the main bathing beach.
Are there properties near the beach available to rent?
Yes. Trearddur Bay Holiday Homes manages over 30 self-catering properties in and around the village, many within walking distance of the beach. Browse availability at our properties page or call 01407 861 788.