The Porthclais Harbour committee started in 1954, although the harbour has been used by boatmen for centuries. We lease the main body of the harbour from the Crown Commissioner through the Pembrokeshire Coast National Parks. Porthclais (also known as Porth Clais) is a small sheltered inlet harbour near St Davids, Pembrokeshire, Wales . Porthclais port 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.