The Blue Lagoon is a disused slate quarry filled with beautiful blue-green water that’s popular with rock climbers and cliff jumpers
Situated just north of Abereiddy beach, the Blue Lagoon was formerly a slate quarry owned by the St Brides Slate Company. The extracted slate was transported by tram to nearby Porthgain and shipped all over Europe. It was in use until 1910 when it was closed and the channel that connected the quarry to the sea was blasted by fisherman which allowed the water to flood in and create a harbour for their boats.
The mineral composition of the slate gives the water its distinctive deep blue hue. Owned by the National Trust and forming part of the Pembrokeshire Coastal Path, the lagoon is 25 m deep and surrounded by rocky cliff formations. During the summer, the site gets very busy with tourists, Instagrammers, and adventure groups.
In 2012 the Blue Lagoon was selected as one of the sites for the Red Bull Cliff Diving World Series. A platform was constructed 27 metres above the lagoon from which 14 of the world’s best divers jumped into the water. The championships returned in 2013 and 2016.
Although the platform built by Red Bull has been removed, there are three permanent diving boards in place. Even if you don’t fancy having a go yourself, it’s fun to pull up a chair and watch as the more intrepid plummet into the cold water from the cliffs above.
The deep, sheltered water is relatively calm and free from currents, so is also a good location for swimming, snorkelling, diving, kayaking, and paddleboarding. If you’re looking for an adrenaline rush, there are several centres nearby that offer days out coasteering at the lagoon and will happily accommodate both families and beginners.
Take in the stunning views along the coastal path and walk past a group of ruined slate cottages. Known as The Row or The Street, they belonged to the workmen but were abandoned at the same time as the quarry itself. You’ll also be able to spot the foreman’s house and the powder store.
Continue two miles on to Porthgain where you’ll find the remains of another quarry including brick kilns and hoppers used to store the crushed stones.
A colony of seals live nearby which can often be seen bobbing about in the water or lazing on the rocks around the lagoon. During pupping season, some parts of the lagoon may be closed off to avoid visitors disturbing the baby seals.
There is a large car park near Abereiddy beach from where it’s a short walk to the lagoon. In peak season it can get very busy and parking attendants may ask you to leave and return in an hour. The path to the lagoon is suitable for pushchairs and wheelchair users.
Public toilets can be found near the car park and in the summer, there is often an ice cream van selling drinks and snacks.
