The Glamorgan Heritage Coast is a wonderful, world-class 14 mile / 23 km stretch of coastline from Ogmore to Aberthaw.
It includes a fantastic beach and bay at Southerndown at the western end, where there is also the Duraven Park and walled garden. There is a lighthouse at Nash Point and the historic St Donats Castle.
There are short and long walks along the coastal path. Look up the 303 bus - it will enable you to do a linear walk without retracing your steps!
When the tide is out it is possible to walk from Dunraven to Llantwit along the rocky and sandy shoreline.