Castell Bach is a small L-shaped beach, just north of Cwmtydu. It is made up of coarse sand and shingle flanked by cliffs of mudstone with two small islets. A large flat area behind the beach was the site of a Celtic iron age settlement at around 300BC, now it's a good place to sit and take in the views. Access to the beach is a scramble down a steep path at the north west corner. Parking is available at Cwmtydu, or slightly nearer roadside parking can be found on the road to St Tysilio's Church at Grid Ref SN363573. From the end of the lane a footpath on the left leads through a field and along a track to the coastal path.