Atami is a famous seaside getaway, developed around a beach, but this being Japan it is the onsen that most local tourists are here for, and they’ve been visiting this area to bathe for centuries. Atami’s proximity to Hakone and Mount Fuji mean it too shares those mineral-rich warm waters, and has many hot bathing destinations to choose from. Most are tied into resorts and ryokan but these do offer some incredibly reasonable day tripper deals.
While Atami might not host the best beach on the peninsula, it is an easy day trip from Tokyo even without a car, something that can’t really be said for all of Izu. The sandy beach is artificial, and so is the town in so many ways: ghost hotels and empty towers dot the crowded bay. If this sounds interesting to you, then take a camera. You won’t be disappointed if dilapidated showa beach resorts are your bag.
The beach is fun. Easily accessed, big enough to not feel crowded unless you visit in the peak summer months, and with a gentle bay you can swim comfortably. After swimming you can find a charming seaside restaurant or izakaya or take a steaming bath to wash off the salt. You could even end the day in Hakone and wake up to a mountain sunrise.