Travelling to Kamakura from Tokyo could not be any easier than getting onto a JR train with your Passmo/Suica card and then getting off at Kamakura. As you get towards the destination, you will see more people in beachwear board the train. We went on a Saturday in early August, it was hot and humid. It is a very short walk to the beach from the station, maybe 15 minutes. There are plenty of shops and restaurants and cafes along the way, as well as a bathing suit store. There is a Hawaiian theme to this place. The beach itself is patrolled and safe, it is clean, family oriented, and one can swim, sunbathe, rest, surf from sun-rise to sun-set. We didn't encounter any negatives, we felt safe the entire time. When someone was taking multiple photographs of an unrelated person, security requested that they stop, very politely. The water is warm, the sandbars go out a few hundred feet. There are good waves when the tide comes in, so there are surfers, but not very many. There are lots of sun-tents as well. There is only one washroom/change room area and one shower/faucet where everyone lines up to wash off the sand at the end of the day, so a bit of a wait. There are bars along the beach for drinking. Tattoos must be covered, no smoking is allowed, no booze allowed. We saw all 3 on the beach, even with the security. There was a Coast Guard helicopter orbiting all day, presumably on shark patrol, although we never saw a fish larger than a minnow. (2 days later a dead baby whale washed up on shore however, which was a first!) There is an air force base nearby so you will see and hear planes and other helicopters fly overhead, but not constantly. Other than that, it is quiet and enjoyable. The Yuigahama beach is literally across the other side of a fresh water creek which you can walk across in 2 seconds, but THAT beach is really crowded, which is why we wandered over to this side.

Zaimokuza is the beach on the Zushi side of Kamakura. I think more people go to Yuigahama beach, on the other side of the little river. Zaimokuza is more for surfers and windsurfers who have exclusive use of the far eastern end of the beach. But it is OK to use the beach for swimming away from this end, which is marked out in Japanese and English signs. Like all beaches in Kamakura, you will find little bars, cafes and clubs, though it is quieter. The sand is soft but can be rather grey. Watch out for crows and hawks! I came here after a visit to Komyoji temple, and it is nice walk back to town