Tenby is postcard Wales: a walled Georgian town on a promontory with four beaches, a working harbour, and rows of pastel-painted houses that have been photographed continuously since the Victorians discovered the place. The medieval town walls still encircle the old town. Caldey Island, a Cistercian monastery, is visible from the harbour and accessible by ferry.
It is genuinely beautiful and genuinely popular in summer, accommodation books out months ahead in July and August. Come in May, September, or even winter for the authentic version: the harbour, the coloured houses, the sea, and very few other people.