The European country that has a coastline along the Adriatic Sea is Croatia. Known for its stunning coastal landscapes, Croatia boasts numerous islands and picturesque towns along the Adriatic coast. Cities like Dubrovnik and Split attract tourists for their rich history and cultural heritage. The Adriatic Sea is essential for Croatia’s economy, primarily through tourism and fishing industries. This beautiful coastline, along with the country's national parks and historical sites, makes Croatia a popular destination for visitors seeking both relaxation and adventure.