Kosai, Japan offers 6 beaches perfect for sunbathing, surfing, swimming, and more. Kosai is known for the Arai Barrier, a historic checkpoint on the Tokaido road. The best time to travel to Kosai, Japan, is in May when the average air temperature is around 20°C (68°F) and the water temperature is approximately 18°C (64°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!
