Chigasaki is a great little beach town with a lot of Hawaiian influence. The city is famous for their surf shops, and even boasts about opening the first surf shop in Japan. You'll see a lot of people wearing Aloha shirts and carrying their surfboards on their bikes as you make the trek from the station to the shoreline.
About a 15 to 20 minute walk from Chigasaki JR Station, Southern Beach is a designated swimming area lined with small bars and rental shops. At the rental shops, you can rent most anything needed for a day at the beach besides your own swimsuit and sunscreen. They offer beach mats, umbrellas, inner tubes, boogie boards, and surfboards. With strong currents and high waves, an inner tube is a great way to stay afloat and venture further from the shore.
After a few hours lounging on the beach, my skin threatened to turn red under the unrelenting sun, so I picked up my things and headed for shelter in one of the many beach shack bars. Some of the beach shacks that I passed by had similar offerings of beer and food, showers and lockers, and family style seating. With the latest J-pop music blasting, people lounged in the large, shaded areas with fans lazily beating against the still air. There was a small kiddie pool for children to play in while their parents relaxed with a cold Asahi.
The bar I visited also offered a water hose for patrons to rinse off the sand and salt before heading home. Free showers are a rare case at Japanese beaches, so the small amenity was much appreciated. Everyone at the bar was extremely friendly, helping me order when I couldn't understand the Japanese-only menu written on the walls. With a cold beer and a hot bowl of ramen, I watched the sunset over Enoshima Island.
The sand at Southern Beach is dark and fine, which in turn makes the water darker than areas like Okinawa and Shirahama in Izu; however, Chigasaki is a great and easy escape from the big metropolis only 25 minutes from Yokohama and 60 minutes from Shinjuku. Lifeguards patrol the beach and announce the time every thirty minutes. Facilities include a small western-style toilet, as well as porta-potties.