Agios Stefanos. Agios Stefanos is a beautiful sandy beach on the south coast of the Greek island of Kos. This beach is in the bay of Kefalos, about 36 km southwest of Kos town. It is a special beach, because the beach itself is next to the ruins of the 5th-century Agios Stefanos basilica. Exactly opposite of Agios Stefanos lies the island of Kastri on which the striking white church with the blue dome of Agios Nikolaos stands. The beach is well organised, and all kinds of water sports are possible here. On the beach there is a canteen where you can order snacks and drinks. The water is shallow at Agios Stefanos, you can almost walk into the sea all the way down to the island. On both sides of the basilica of Agios Stefanos are beautiful beaches.