The Gulf of Trieste (Italian: Golfo di Trieste, Slovene: Tržaški zaliv, Croatian: Tršćanski zaljev, German: Golf von Triest) is a very shallow bay of the Adriatic Sea, in the extreme northern part of the Adriatic Sea. It is part of the Gulf of Venice and is shared by Italy, Slovenia and Croatia. It is closed to the south by the peninsula of Istria, the largest peninsula in the Adriatic Sea, shared between Croatia and Slovenia.