The Blue Lagoon's deep blue color is the result of slate waste materials settling at the bottom, which creates a specific light-reflective environment.
The area is an internationally significant geological site, featuring well-preserved fossils of graptolites, which are extinct colonial marine organisms.
The beach is a frequent location for adventure sports including coasteering due to its rugged cliffs and sheltered lagoon access.
The Pembrokeshire slate industry that operated here exported materials globally during the 19th century before flooding ended production.
Abereiddy Beach is defined by its dark, slate-grey sand and its proximity to the Blue Lagoon, a flooded former slate quarry. The beach is located within the Pembrokeshire Coast National Park and features distinct geological strata visible in the surrounding cliff faces. The Blue Lagoon is separated from the main beach by a low headland and is notable for its vivid turquoise water caused by mineral content and depth. The site was historically the hub of the Pembrokeshire slate industry until the quarry was breached by the sea in the early 20th century. Visitors can access the Pembrokeshire Coast Path directly from the beach, which serves as a popular trailhead for coastal hiking. The beach is prone to strong currents and is largely composed of pebbles and coarse sand, making it less suitable for traditional sandcastle building. The site remains an open, natural environment with limited commercial infrastructure on-site.
The elevated path overlooking the Blue Lagoon provides a wide-angle view of the turquoise water against the dark slate cliffs.
Bring sturdy footwear, as the beach is rocky and the path to the Blue Lagoon involves uneven slate scree.
Check local tide tables before visiting, as the beach shrinks significantly at high tide.
Bring a wetsuit if you intend to swim in the Blue Lagoon, as the water remains cold even in summer.
Do not jump from the high walls of the Blue Lagoon, as this is discouraged by local safety authorities due to hidden debris underwater.
Take all trash with you as there are no bins on the beach; respect the fragile cliff environment by staying on marked paths.
