Ravines and gorges end at small coves with sandy beaches. Depending on your mood and the existing winds they are accessible by car, trail or boat.
For the more secluded beaches, in some cases a small 4X4 vehicle is advised. Good options include on the east side Sykamia (non organized, unsurfaced road), Spathi (nice view on route, organized, unsurfaced road), Psathi (non organized, unsurfaced road), Kaliskia (non organized, 4X4 vehicle), and Tylegraphos (non organized, 4X4 vehicle). On the south Koundouraki (asphalt, organized, ideal for watersports, http://www.kwsports.gr/) and on the west Xyla & Vroskopos (non organized).
If you are a vivid hiker then you must not miss on the eastern side the beach of Aghios Filippos (also by boat) and the beaches at Poles bay next to the ruins of ancient Karthea.