Ireland’s coastline is 3171 kilometres long, according to the Ordnance Survey. Some other sources claim it extends for over 5,631 km (3,500 miles), and one puts it at 7500km “if you include all the way up the estuaries, bays and inlets etc.”
A basic distinction must be made between westerly shores exposed to the full force of the Atlantic Ocean and the more sheltered east coast.
At Slieve League in County Donegal, the cliffs reach heights of over 600m. Actively eroding cliffs are widespread along the west coast, (e.g. the famous Cliffs of Moher in County Clare and Croaghaun on Achill Island, County Mayo), and also the east (Killiney, County Dublin, around Bray Head in Counry Wicklow, and at Blackwater in County Wexford, where the soft boulder clay materials along the shore are highly vulnerable). In the south, at the spectacular Old Head of Kinsale, only a thin neck of land now joins the resistant sandstone headland to the ‘mainland’ coast of County Cork
Long sandy beaches are a feature of much of the east coast, most notably the great stretch that runs from Cahore Point in County Wicklow south to the Raven at Wexford Harbour.