The water around Anglesey is cold. Let’s get that out of the way first. Even in August, the Irish Sea sits at 15–17°C — a temperature that rewards a wetsuit for anyone planning to stay in longer than 10 minutes, and that produces a particular quality of clearness and aliveness that southern European seas rarely manage. Once you’re in, it’s extraordinary. The challenge is getting in.
Here’s where to swim, and what you need to know before you do.
Safety first — always
Wild swimming around Anglesey carries real hazards that don’t apply to supervised beaches. Before getting in anywhere on this list:
- Check tide times. The tidal range on Anglesey is significant. Spots that look calm at low water can be dangerous at high tide, and tidal currents in channels (the Menai Strait, around headlands) run fast.
- Don’t swim alone. This is not a rule to break on exposed coasts.
- Wear a tow float. It makes you visible to boats and gives you something to rest on. Non-negotiable for open water.
- Check the weather. Onshore winds create confused chop and rip currents. Even calm-looking bays can have surface turbulence in south-westerlies.
- Tell someone. Before you swim anywhere remote, tell someone where you’re going and when you expect to be back.
The RNLI responds to around 80 incidents on the Anglesey coast each year. Most involve overestimating conditions or underestimating tides. The water is not forgiving, but it is manageable for swimmers who are honest about it.
1. Trearddur Bay — the beginner’s choice
Trearddur Bay is where to start if you’re new to wild swimming on Anglesey. The horseshoe cove on the west coast of Holy Island is the most sheltered bay on the exposed western seaboard — the headlands break the swell and the wind, the bottom is sandy and slopes gently, and the water temperature in August can reach 17°C, which is warm by local standards. There are facilities in the village, lifeguards in summer, and the surrounding headlands provide shelter for experienced swimmers who want to explore further.
What to expect: Clear water over sand and rock. Visibility excellent in calm conditions. Snorkelling off the northern headland (wrasse, pollack, the occasional grey seal) is excellent.
Getting there: Postcode LL65 2YD. Pay-and-display car park at the beach.
2. Porth Dafarch — the snorkeller’s cove
Two miles south of Trearddur Bay, Porth Dafarch is wilder and quieter — a sheltered horseshoe on the southwest coast of Holy Island with underwater ledges that hold one of the best snorkel environments in Wales. Bass, wrasse, pollack, and kelp forests extending down past 5 metres. On still days in late summer the visibility can reach 8–10 metres.
What to expect: Rocky edges with sand in the middle of the cove. The headlands shelter from the prevailing south-westerly but some swell penetrates in stronger winds. Not suitable in onshore conditions.
Getting there: Pay-and-display above the beach. Postcode LL65 2LT. No café — bring provisions.
3. Silver Bay — evening light swim
Silver Bay near Rhoscolyn earns its name in the late afternoon when the Atlantic light hits the water from the southwest. It’s a small, crescent-shaped beach on the western coast of Holy Island — sheltered, shallow, and with a sandy bottom that makes it gentle for open water swimming. The surrounding headland is designated SSSI for its maritime heathland, and the coastal path to Rhoscolyn Head gives you the best views of what you’re swimming in.
What to expect: Calm, sheltered swimming in good conditions. Some tidal movement around the headlands — swim within the bay rather than around the points.
Getting there: Limited parking near Rhoscolyn village (LL65 2AZ). Some walking required.
4. Lligwy Beach — east coast clarity
Lligwy Beach on the northeast coast near Moelfre faces north — which means it catches the cleanest water coming off the Irish Sea without the murk stirred up by southern exposures. The water quality here is consistently good, the beach is rarely crowded, and the rock shelf at the northern end provides depth changes and interesting terrain for snorkellers.
What to expect: Good clarity on calm days. East-facing beaches are warmest in the morning. Mild tidal movement — check before swimming off the rock shelf at the far end.
Getting there: Pay-and-display car park. Postcode LL72 8NL.
5. Newborough Beach — long swim in big water
Newborough Beach offers the longest swim of any accessible beach on the island — a broad, flat shore with consistent water quality and the Snowdonia peaks across the water for orientation. At low tide the beach stretches for well over a mile, and the water over the firm sand is clear and manageable.
Caution: Don’t swim toward Llanddwyn Island without understanding the tidal currents around the peninsula — the flow around the point can be strong at certain states of tide. Swim parallel to shore rather than toward the island.
What to expect: Flat water in calm conditions over firm sand. Best at low tide on a still morning.
Getting there: ANPR cashless parking, £5 for 2 hrs or £15 all day. Postcode LL61 6SG.
6. Church Bay — northwest wild swim
Church Bay (Porth Swtan) on the northwest coast is about as remote as accessible wild swimming gets on Anglesey — tucked between headlands, faces west, and rarely busy even in summer. The water here is open Atlantic; there’s no shelter from the deep Irish Sea, which means water quality is exceptional and clarity is very good on calm days. The flip side is that it’s exposed — only swim here in settled weather.
What to expect: Clear, cold water (typically 1–2°C colder than sheltered bays). Significant swell in any wind. Beautiful on calm days in late summer — one of the finest swimming spots on the island if conditions are right.
Getting there: Small car park above the beach. Postcode LL65 4ET.
Water temperature guide
| Month | Typical sea temp | Notes |
|---|---|---|
| Jan–Mar | 8–10°C | Dry suit territory. Not recommended without thermal protection. |
| Apr–May | 10–12°C | Wetsuit essential (5mm). Short swims possible for acclimatised swimmers. |
| Jun–Jul | 13–15°C | 3mm wetsuit comfortable. Open water season begins properly. |
| Aug–Sep | 15–17°C | Peak temperature. 3mm wetsuit or tow float skins for shorter swims. |
| Oct–Nov | 13–15°C | Cooling but still swimmable with 4mm wetsuit. Uncrowded beaches. |
| Dec | 10–12°C | Cold water swimming community active. Wetsuit essential. |
Kit list
- Wetsuit: 3mm minimum for summer; 4–5mm for spring and autumn.
- Tow float: Makes you visible and gives you a rest point. Mandatory in my opinion.
- Neoprene gloves and booties: Hands and feet feel the cold first. Worth it from October onward.
- Dry robe or changing poncho: The wind on Anglesey’s coast is relentless. Having something warm to put on immediately after getting out is not optional.
- Tide table: The BBC or Met Office tides pages are accurate for Anglesey.
Wild swimming on Anglesey rewards the prepared. The cold, the clarity, the seals watching from the rocks, the kites in the air above Rhosneigr while you’re bobbing in the Atlantic — there’s nowhere quite like it. Just check the tides first.