At a glance
Anglesey's largest lake — RSPB managed reservoir for wintering whooper swans (200+), diving ducks, and breeding waders. Lakeside walk (~5 miles), brown trout fishing (permit required), and birdwatching hide. Best October–March. Llanerchymedd 2 miles. LL77 7TF.
About Llyn Alaw
Llyn Alaw is the largest lake on Anglesey — a reservoir occupying the shallow valley of the Afon Alaw in the island's centre-north, managed by the RSPB as a significant site for breeding and wintering wildfowl. The lake has a very different character from the mountain lakes of mainland Snowdonia: flat, open, and set in a lowland agricultural landscape typical of Anglesey's interior, with views extending to the island's northern coast on clear days. The habitat — a shallow, nutrient-rich reservoir surrounded by improved grassland and rough grazing — suits the dabbling and diving ducks, waders, and swans that are the lake's wildlife signature.
Winter (October to March) is the best season. Whooper swans arrive from Iceland to winter at the lake — numbers can exceed 200 — alongside large flocks of teal, wigeon, pochard, tufted duck, and goldeneye. A hide at the northern end gives sheltered views across the open water. In summer, the RSPB manages the surrounding farmland for breeding lapwing, curlew, and snipe — species that have declined sharply across lowland Britain and are still relatively common on Anglesey's managed land. Little grebe and tufted duck breed on the lake itself.
The lakeside path provides approximately 5 miles of level walking around the reservoir perimeter. The flat Anglesey landscape means no significant ascent but good open views. Trout fishing (permit required) is a further draw. Cemlyn Bay, the RSPB tern colony on the north Anglesey coast, is 8 miles north — the two sites make a natural wildlife pairing for a full day of Anglesey birdwatching.
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Frequently asked questions
Llyn Alaw is managed by the RSPB as an important site for wildfowl throughout the year. In winter (October to March), the lake is a significant site for whooper swans — up to 200 or more may be present — along with large numbers of diving ducks including goldeneye, tufted duck, and pochard. Teal, wigeon, and other surface-feeding ducks use the shallower margins. In summer, the lake supports breeding lapwing, curlew, and snipe on the surrounding farmland, and little grebe and tufted duck on the water itself. The RSPB manages grazing and water levels to maximise the habitat quality for breeding and wintering species.
Llyn Alaw is one of the better fishing lakes on Anglesey — stocked with brown trout and with a limited number of day tickets and season permits available. The lake is owned by Welsh Water; fishing permits and boat hire are managed separately and can be obtained from the Alaw Angling Club or from local tackle shops. The lake's good-sized trout make it attractive to fly fishers. Bank fishing from designated areas and boat fishing are both possible. The best fishing season is typically April to October, with brown trout the main quarry. Check the current permit arrangements before visiting, as management can change.
A lakeside path circles part of Llyn Alaw, giving access to the water's edge for birdwatching and fishing. The path is largely flat — characteristic of Anglesey's low-lying landscape — and passes through the farmland habitat that the RSPB manages for breeding waders. The circuit around the full perimeter of the lake is approximately 5 miles. The path can be muddy in wet weather, particularly in winter and early spring. The car park at the reservoir is the most convenient starting point; a basic hide at the northern end of the lake gives sheltered views across the water.
Llyn Alaw is the largest lake on Anglesey — significantly larger than the other inland lakes on the island such as Llyn Coron (south of Aberffraw) and Llyn Llywenan (near Llanerchymedd). Its size and the RSPB management make it the most important inland water on the island for wildlife. Anglesey's inland lakes are generally shallow and nutrient-rich — quite different in character from the deep, cold mountain lakes of mainland Snowdonia — and attract different bird species: the lowland dabbling and diving ducks rather than the red-throated divers and goosanders more typical of upland waters.
Llyn Alaw is in central-northern Anglesey, approximately 2 miles north of the village of Llanerchymedd and 5 miles south of Amlwch on the north coast. Access is by minor roads from the B5111 or from Llanerchymedd. There is a car park at the reservoir. The lake is not on a main tourist route but is accessible from Amlwch (5 miles), Beaumaris (10 miles), and Holyhead (14 miles). For visitors spending time on Anglesey combining wildlife sites, Llyn Alaw pairs well with Cemlyn Bay (RSPB tern colony, 8 miles north) and South Stack RSPB reserve (14 miles west).