How can a person protect valuables when taking a bath in a mixed bed room of a youth hostel?

There is usually a locked cabinet. If not, you can store it at the counter. If it's only a small thing, I think you can take it with you. Take it in a waterproof bag when you take a shower. In fact, I usually get to know a girl first, and then we can talk about it. After getting familiar with it, I can add a WeChat or something and let others take care of it.