Diamond Beach, Australia offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Diamond Beach, New South Wales, Australia, is known for its pristine beaches and the nearby Booti Booti National Park. The best time to visit Diamond Beach, Australia, is from December to February, 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!