Is Thermae-Yu (Shinjuku urban onsen) worth it solo?
Worth itSolo
Solo, Thermae-Yu (Shinjuku urban onsen) works.
An honest in-the-city onsen reset: Thermae-Yu sits a short walk from Shinjuku Station and pipes in genuine natural hot-spring water (trucked daily from a Gifu source) for its baths and open-air tubs, plus saunas and lounging floors. What makes it the right pick over the generic 'urban spa': it's one of the more tattoo-tolerant onsen in Tokyo — small/'fashion' tattoos are allowed if covered, with ¥300 cover stickers sold on-site (max two) — and it's walk-in, roughly ¥1,000-3,000. Bathing is still communal and gender-separated, so a couple parts ways inside.