Croatia and Slovenia border what sea?

Croatia and Slovenia border the Adriatic Sea. The sea lies between Italy’s peninsula and the Balkan Peninsula, and its northeastern shoreline includes both countries. Croatia has a long, deeply indented Adriatic coast, while Slovenia has a much shorter coastline centered on the Gulf of Trieste.

Slovenia’s coastal towns include Koper, Izola, and Piran. Croatia’s Adriatic side includes major ports and tourist cities such as Rijeka, Split, Dubrovnik, and Zadar, along with more than a thousand islands and islets. The Adriatic is a semi-enclosed sea connected to the Ionian Sea through the Strait of Otranto.

A common mix-up concerns the Gulf of Trieste and the Gulf of Piran. These are smaller gulfs within the northern Adriatic, not alternative names for the entire sea. Croatia and Slovenia have disputed parts of their land and maritime boundary, especially around the Gulf of Piran, but that political disagreement does not change the geographic answer. Both countries are Adriatic states.