Shirahama Ohama is Shimoda's main beach, a long curve of pale sand about 4 km northeast of the centre. The water is clear, the sand is better than most beaches this close to Tokyo, and the surf is strong enough to keep board riders interested when conditions are right.
Summer weekends can be busy, but the beach is still the reason many travellers come down the Izu Peninsula. Buses run from Izukyu-Shimoda Station, making it workable even without a car.