Hidden Island, Australia offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Hidden Island, Western Australia, Australia, is known for the Buccaneer Archipelago and its stunning natural beauty. The best time to travel to Hidden Island, Australia, is from May to September, with average air temperatures around 25°C (77°F) and water temperatures near 23°C (73°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!