Marion Bay, Australia offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Marion Bay is known for its proximity to Innes National Park and the stunning coastal scenery of the Yorke Peninsula. The best time to travel to Marion Bay, Australia, is during the summer months of December to February, when the average air temperature is around 25°C (77°F) and the water temperature is approximately 21°C (70°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!