It’s hard to believe that there’s any sort of beachy, “surf’s up, Dude!” culture in Tokyo, but there certainly is if you take the JR East Yokosuka rail line about an hour south of the city, to Zushi Beach.
It is less well known but not much less crowded than the beaches at Kamakura, and is very popular with windsurfers (and surfers, whenever a freighter steams past and some waves roll in.)
July and August are the “official” beach season. Like so much else in very orderly Japan, the Polynesian-style thatched hut beer joints and fish taco stands don’t begin to appear on the rather grubby sands until it is officially time to appear, then they sprout overnight and disappear as quickly at the end of August.
Rather than spend the ridiculous amount of Yen that you’ll be charged for a beachside meal, head inland a little and go Hawaiian at Vahana’s Bar in Zushi.
It’s a two-story building on a main street in Zushi, with palm fronds and surfboards hanging all over it.
There’s a pretty extensive menu, friendly staff, frequent live music and lots of locals.
Beats the heck out of some overpriced, pretentious club in Roppongi.