The Gulf of Trieste (Italian: Golfo di Trieste, Slovene: Tržaški zaliv, German: Golf von Triest ) is a shallow bay of the Adriatic Sea, in the extreme northern part of the Mediterranean Sea. It is part of the Gulf of Venice , and is shared by Italy, Slovenia and Croatia. The Gulf is limited by an imaginary line connecting the Punta Tagliamento on the Italian and Savudrija - Capo Salvore on the Croatian coast. Its area is approximately 1000 km², its average depth 16 m, and its maximal depth 37 m. With the exception of flat islets blocking the entrance to Laguna del Grado, there are no islands in the gulf. Its eastern coasts, with Trieste and the Slovene littoral , have more rugged relief; the most prominent features are Bay of Muggia , Bay of Koper - Capodistria and Bay of Piran - Pirano .