Pen-y-Cwm beach is at the northern end of Newgale Sands and the north-eastern corner of St Brides Bay. It can be reached at low to mid-tide by walking along the shore from Newgale, and at other times via the coastal path. Alternatively, from Pen-y-Cwm on the A487, a public footpath follows the valley down to the beach, and roadside parking can be found in Pen-y-Cwm.
The beach is of course sand and light shingle, with rocks, rock-pools and a walk-through cave. It looks out towards Skomer Island to the left and Grassholm Island straight ahead, some 17 miles offshore. The cliffs are of sandstones, conglomerates and shales.
The small cove of Cwm-bach is further to the north, and is sandy and backed by purple sandstone boulders and cliffs. It can only be reached along the shore at low tide, but even so, this will usually entail some paddling or walking over the rocks.