Wear your birthday suits in public baths
That’s right. When you enter a public bathhouse, you need to strip down to your birthday suit before jumping in (don’t literally jump in). That’s just how it is in Japan, and you’ll be asked to leave if you try to force your way in with swimming trunks.
Yes, it’s uncomfortably for tourists at first, and many of them decide to avoid public bathhouses altogether. However, if you really want to enjoy a relaxing day at a spa, then we say stifle your modesty and uncover your shame. That’s just some advice for you. We’d rather avoid these places.