Porthclais harbour was built in the 12th century and supplied St Davids with imported coal and timber. It is still used as a small port by both local fishermen and recreational sailors. The old harbour wall, built by the Romans according to some legends, is largely intact. The harbour dries out at low tide and is a good launching spot for small boats, dive craft and kayaks who are setting out to explore St Brides Bay.
There is a car park on the site of what used to be the now defunct St. Davids gasworks, which in turn was built on the site of a spring where it is said St. David himself was baptised.
Porthclais is also purported to be the landing place of Twrch Trwyth, the legendary magical boar which swam from Ireland to confront King Arthur.
Around the harbour is evidence of lime kilns.
There is a small café sited on the old gas works which is open in season.
Porthclais is accessed by road South west of St Davids and also the coast path passes through – not literelly- the harbour.