Croatia and Slovenia have disputed their land and maritime boundaries ever since both States gained their independence from Yugoslavia in 1991. After decades of failed negotiations, Croatia and Slovenia signed an agreement to take their dispute to the Permanent Court of Arbitration on 4 November 2009. The proceedings for their case were interrupted in 2015 by a scandal that prompted Croatia to unilaterally terminate the Arbitration Agreement.

In a Partial Award made on 30 June 2016, the Tribunal ruled that even though Slovenia had in fact breached the terms of the Arbitration Agreement, the Tribunal still had jurisdiction to continue its deliberations and issue a final award. The Tribunal delivered their Award on 29 June 2017, which provided rulings on both the land and maritime disputes. However, Croatia has remained steadfast in its refusal to recognize the legitimacy of these findings due to the breach in protocol that prohibits either Party’s legal team from having contact with members of the Tribunal prior to its Award.

The maritime boundary between Croatia and Slovenia, as delimited by the 2017 Award, begins at the land boundary terminus where the St. Odoric Canal empties into the Bay of Piran. From this point the Tribunal defined a geodesic line segment that proceeds out to point A located on the bay closure line. From point A the boundary then delimits the overlapping territorial sea entitlements of the Parties by following a modified equidistance line for just under seven nautical miles until it reaches point B located on the 1975 Italy–Yugoslavia territorial sea boundary.

The Tribunal also granted Slovenia a junction area in which they would enjoy the freedom to navigate through Croatian territorial waters until their vessels reach waters beyond 12 M from Croatian land territory, a position viewed in the Mediterranean as the starting point of the high seas.