Zlarin, Croatia offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Zlarin, Sibenik Knin, Croatia, is known for its coral diving and the historic Coral Museum. The best time to travel to Zlarin, Croatia, is from June to September, when the average air temperature is around 75°F (24°C) and the sea temperature is approximately 77°F (25°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!