Porthclais harbour was built in the 12th century, importing coal and timber. The entire harbour is within the St David's Peninsula
Site of Special Scientific Interest. Porthclais is still used as a small port by local fishermen and recreational sailors. The largely intact old harbour wall may have been built by the Romans, and the harbour was mentioned in the mediaeval
Mabinogion. The earliest recorded date of trade through the port is 1385. 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 Bride's Bay. Porthclais harbour has some of the best preserved remains of stone
Lime kilns in
Pembrokeshire. ==Harbour authority==