- The Ionian Sea (Modern Greek: Ιόνιο Πέλαγος, romanized: Iónio Pélagos, IPA: [iˈoni.o ˈpelaɣos]; Italian: Mar Ionio or Mar Jonio, IPA: [mar ˈjɔːnjo]; Albanian: Deti Jon, IPA: [ˈdɛti ˈjɔn]) is an elongated bay of the Mediterranean Sea. It is connected to the Adriatic Sea to the north, and is bounded by Southern Italy, including Basilicata, Calabria, Sicily, and the Salento peninsula to the west, southern Albania (and western Apulia, Italy) to the north, and the west coast of Greece, including the Peloponnese.