Abercastle is a small harbour / beach on Pembrokeshire's north coast. A small (free) parking area overlooks the beach and access to the shore is down a short slipway. Facilities here include (seasonal) toilets and a picnic table. The village of Trefin is a short walk away, and has a cafe and a pub.
The beach is mostly seaweed strewn sand, with the headland on the west side becoming an island on the high tide.
It's very sheltered and is popular with anglers, canoeists and divers. The fragmented wreck of the Leysian - a steamship which hit rocks in February 1917 on its way to Barry - is situated just outside the bay at about 15 metres depth.