Ustrine, Croatia offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Ustrine is known for its proximity to the ancient Roman settlement of Fulfinium and the beautiful beaches of Cres Island. The best time to travel to Ustrine, Croatia, is from June to September, with average air temperatures around 75°F (24°C) and water temperatures about 73°F (23°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!