Kamata Onsen

Kamata Onsen is a nostalgic public bathhouse that has been in operation since 1937. The naturally sourced hot spring water that flows here is jet black - considered the darkest among Kamata’s many black-hot-spring baths. This distinctive color comes from humic acid, which is rich in marine minerals. Despite its appearance, the water has no unpleasant odor, making it approachable even for first-time visitors.

The spring quality is classified as sodium bicarbonate and chloride mineral springs, often praised as “beauty baths” for their skin-smoothing effects. The water is not diluted and flows directly from the source, giving it a slightly viscous texture. After bathing, the skin feels soft, moisturized, and silky smooth, while the heat retention helps prevent chills and supports fatigue recovery. The black-hot-spring tubs include both one of Tokyo’s hottest baths and a low-temperature option - perfect for those who enjoy an intense soak or a more relaxed experience.

In addition to the black water baths, the facility offers a variety of options including an electric bath, jet bath, sauna, and cold plunge pool, allowing guests to unwind and soothe their bodies at their own pace.

After bathing, head to the on-site diner, which opens from noon. A cold beer after your soak is hard to beat! Particularly popular dishes include the hot spring kamameshi (rice cooked in an onsen pot) and salt yakisoba, while shaved ice is available year-round.

The shop is also worth a visit, with the most popular item being T-shirts featuring a cool retro logo and bold kanji design. Stickers, tenugui towels, and other unique goods make perfect souvenirs or personal keepsakes.