Toshimaen Niwa no Yu
Niwa no Yu includes separate male and female onsen and outdoor jacuzzis surrounded by Japanese gardens. The water is rich in sodium chloride, a salt rumored to ease muscle pain and joint stiffness. For the ultimate experience, there’s even a restaurant on the premises. It’s a very adult-friendly environment, and children under the age of 13 are denied entry.
Somei Onsen Sakura
Somei Onsen Sakura takes its name from the cherry trees sprucing up the property. This makes it a popular choice in spring when the trees are in full bloom. They offer a wide variety of services, from dining and yoga classes to massage and lounge spaces.
Myojin no Yu
Myojin no Yu is an attractive, traditionally styled bathhouse. The waters are rich in iron and other salts, said to be the solution for a wide range of body aches, pains, and complaints. Only the main indoor cypress-wood tubs are filled with water from their spring; the outdoor bath is on the city’s water main.
Oedo Onsen Monogatari
Oedo Onsen Monogatari is an onsen-themed theme park in Odaiba. It’s home to six different types of baths, a tub for dogs, and wading pools ideal for cooling off in the summer heat. The onsen here are fueled with thermal spring water deep beneath the Earth and are rich in sodium ions. After 2 AM, a late-night fee of ¥2,000 is added.
Take no Yu
Take no Yu has been operating for nearly one hundred years. The waters here are dark, blackish, and mineral-rich, nicknamed ‘Black Beautifying Water.’ There are also gender-segregated saunas and even laundry facilities. Take no Yu has a simple, no-nonsense sento-like setup for the serious bather.
Heiwajima Natural Hot Spring
The water of Heiwajima’s hot springs come from deep underground. It’s open 24 hours and offers a shuttle service to and from Haneda Airport each morning, so it’s the ideal way to spend a long layover. They keep a list of departure times and even offer reservations on their website in English, Chinese, and Korean to cater to the wide variety of guests. A huge variety of spa and massage services are available.