The Myrtoan Sea (Greek: Mυρτώο Πέλαγος, Myrtoo Pelagos, Greek pronunciation: [miɾˈto.o ˈpelaɣos]), also written as the Mirtoan Sea, is a subdivision of the Mediterranean Sea that lies between the Cyclades and the Peloponnesos. It is described as the part of the Aegean Sea south of Euboea, Attica, and Argolis. Some of the water mass of the Black Sea reaches the Myrtoan Sea, via transport through the Aegean Sea. (Saundry, Hogan & Baum. 2011)
It is said to have been named after the mythical hero Myrtilus, who was thrown into this sea by an enraged Pelops. The name has also been connected with that of the maiden Myrto. It is also said to have derived its name from a small island named Myrtus.