Trstenik, Croatia offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Trstenik, Dubrovnik Neretva, Croatia, is known for its proximity to the renowned wine-producing region of the Peljesac Peninsula and the beautiful beaches along the Adriatic Sea. The best time to travel to Trstenik, Croatia, is from June to September, when the average air temperature is around 77°F (25°C) and the water temperature is approximately 75°F (24°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!