Mission Beach, Australia offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Mission Beach is known for the Great Barrier Reef, Dunk Island, and the Cassowary Coast. The best time to visit Mission Beach, Australia, is from May to September, when the average air temperature is around 25°C (77°F) and the water temperature is approximately 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!