Manza Beach
Here is something to spoil yourself; Manza Beach. It's owned and operated by the Manza Beach Hotel and Resort. Entry is 1000 yen per car and 500 yen for motorcycles. This is one of the best swimming beaches I have seen. If you have kids you can lay back and relax. The swimming area is perfectly save with a lifeguard on duty. There are beachside showers, restrooms, and even a pool. You can rent anything from a chair to snorkel gear. Go parasailing or windsurfing. All for a prices of course, yet very nice.

