Which body of water does Turkey share with another country?

Turkey shares the Aegean Sea with Greece, which makes this body of water significant as it serves as a border between the two nations. The Aegean Sea is characterized by numerous islands, many of which belong to Greece, and it plays a crucial role in trade and maritime activities for both countries. This strategic waterway has historical significance as well, being a key area in ancient maritime routes.

The other bodies of water listed do not share such international boundaries. The Sea of Marmara is entirely within Turkey, acting as a connection between the Aegean Sea and the Black Sea via the Bosporus and the Dardanelles, which are also significant yet exclusively internal waterways that connect different bodies of water but do not share them with other countries. The Bosporus and the Dardanelles specifically are straits that serve as focal points for maritime traffic but remain under Turkish jurisdiction. Thus, the Aegean Sea is the only option that represents a shared body of water between Turkey and another sovereign state.