The Balkan Peninsula is surrounded by the Adriatic Sea to the west, theMediterranean Sea (including the Ionian and Aegean seas) and the Marmara Seato the south and the Black Sea to the east.
There are four seas that share a border with the Balkan region, these are Adriatic Sea, the Black Sea, the Ionian Sea, and the Aegean Sea. Hope this helps.
