There are two sections of cliffs. The tidal island itself, which has some sections of good rock on the South face and Swanbridge, on the mainland side, a little further East than the East end of the island itself.
The crag was visited by Phill Thomas, Andy Sharp and others in the early 1970s but no records of ascents were kept - most of the obvious routes will have been climbed then, so if you have first ascent information, or have done the routes before 2010, please claim and name and they will be adjusted so. The bouldering is new.
It is mostly a bouldering spot with a mix of rock types, both soft red sandstone and hard grey limestone. The bouldering is on the limestone with occasional use of the sandstone for footholds.
Swanbridge itself is sea-washed about an hour either side of higher high tides only. It consists of an excellent bench of very sharp crystalline rock with some good long traverses and a 15ft slab off to the East. It is accessed by walking East along slabs from Swanbridge beach. The bouldering keeps strictly off the red sandsone band for footholds unless specifically mentioned.
Sully Island is accessed via a natural tidal causeway, which disappears extremely quickly once the tide starts to rise. Visitors should check the tide times carefully, bearing in mind that it takes about 15 minutes to cross back to the mainland. Usually a safe window is about 2.5 hours either side of low. From the Penarth to Sully road, turn down the Swanbridge road sign posted to the Captain's Wife and park there to access the beach.