Cold Knap beach consists of a steep bank of pebbles, with some sand at low tide. The car park runs along the back of the beach, but parking on the pebbles is not allowed. To the west the pebble bank is backed by high limestone cliffs, and fossils can be found here (mostly gryphaea and ammonites). At the eastern end of the beach is Cold Knap Point, and a wide promenade behind which is Romilly Park.
Facilities at the beach include toilets, a cold water shower and usually a catering van. There are a few cafes about 200 yards away on Bron-Y-Mor (road) which you have to pass to reach the car park. Dog restrictions apply from 1st May to 30th September on a section of the beach from Cold Knap Point to approximately halfway along the car park. Dogs are allowed at the Porthkerry end. It's a popular location for surfing, at low to mid tide before the waves hit the shingle bank, but tends to be flat in summer. A rip current often occurs at Cold Knap point. The water quality at this beach isn't too good.