Which gulf is shared by Italy, Slovenia and Croatia and contains the entire Slovenian coastline? The Gulf of Trieste is.
The Gulf of Trieste is a shallow northern Adriatic gulf shared by Italy, Slovenia and Croatia. The entire Slovenian coastline lies within it, including the coastal towns of Koper, Izola and Piran. Slovenia’s coastline is only about 46.6 kilometres long, making the gulf especially important to the country’s maritime geography.
The gulf covers approximately 550 square kilometres and has an average depth of about 18.7 metres, with a maximum depth near 37 metres. It is part of the larger Gulf of Venice and is bounded to the south by the Istrian Peninsula. Its waters have some of the Adriatic’s largest tides, though tidal changes normally remain below 60 centimetres.
Several smaller features lie within the gulf, including the Gulf of Koper and Gulf of Piran. The latter has been the subject of a maritime boundary dispute between Slovenia and Croatia since 1991, but it is a sub-gulf rather than the name for the entire shared body of water.