My favorite beach this summer is the Isshiki beach.
There are many beach around Zushi area, and definitely it is a must beach to
stop by during the summer. Around Zushi, there are plenty of music festivals too.
The Isshiki Beach is about 10-15 minute ride by bus from Zushi Station.
(JR Yokosuka Line, about 1 hour away from Tokyo), not too crowded, clean and nice people.
My favorite beach house this summer is Cafe de Rope La Mer. It is just 1 minute walk from Isshiki Kaigan Bus station. The beach house is a little different from the typical Japanese beach house (called "umi no ie") . This one is with some STYLE! The house is architecturally chic plus good music with DJ!
The water is not perfectly transparent, but it is swimmable and no harsh waves.
After a good swim, a frozen mojito, would make you summer unforgettable! :) YAY!!
Here is the link to the beach house. http://cafederope-lamer.jp/