Following C107, I went to my first public bath / onsen. As you might imagine, I have avoided doing this for the usual reasons. I wanted to explain my thoughts on this because I'm really positive on the experience now! Toyosu Manyo Club (EN) offers Comic Market discounts, which made it an attractive thing to try, so I did. I also felt very welcomed, in the sense that “hey, if they're directly saying Comiket attendees can come, that must be mean they're going to be a suitable place for otaku to visit after.”

This is my first onsen experience, and I feel as a foreigner living in Japan, I should clarify that I don't have any experience with prior public bath houses and I wasn't sure what to expect. Maybe this is one of those times (like doctors) where having things in English is super helpful. I hope this is useful to you if you find yourself in similar shoes.

This experience will be about Toyosu Manyo, but I've been informed that many elements are similar to public bath houses or other onsens. Obviously actual facilities will vary depending on the location, but the general elements will remain the same.

If you have a tattoo you can't cover using the provided coverings, you can't use the public bath.

Public baths in Japan are, fundamentally, gender separated baths where you completely undress, wash yourself in public, and subsequently, visit the public bath area or onsen. They also include a “rest” area where you can lay down, temporary yukata to wear during your visit, food, drinks, and other such amenities.

The general flow will be like this:

1. Check-in, and get your locker key / IC chip. You will use this to pay for things instead of payment, since you likely won't have your usual payment methods at least sometimes.
2. Take off shoes before entering.
3. Go to locker changing room.
4. Put everything, and I do mean everything into a locker.
   1. Small towels are available. You probably don't actually need to cover yourself with a towel, but you can.
5. Enter the main washing area.
6. Wash yourself! There is shampoo, body wash, scrubbing instruments, razors, shaving cream, tooth brushes, etc. available.
7. Rinse fully.
8. Splash a bit of onsen water on yourself before getting into the onsen.
9. Get into the onsen! You are now in the onsen.
10. Once you're done relaxing, get a towel, dry completely off, exit into changing room.
11. Put on yukata.
12. Go to relaxation room, relax, or get food, etc.
13. When you're fully done, go back to locker, swap into your normal clothes, deposit yukata and return.
14. Pay.
15. Put shoes back on.
16. Leave

So the main reason why most people are scared or apprehensive about public baths is because being naked is generally not a thing people do together in the west. Allow me to provide some useful advice: nobody, and I do mean nobody, cares.

To put it differently, even as a foreigner, you won't get stared at or questioned, or anything. Now, obviously, people can see you naked, but that really is not a problem. I know this is a crazy rubicon to cross, but on a fundamental level, people do not judge you. You are probably judging yourself more than anyone else will. If you stare at someone naked obviously that's a separate issue, but don't do that. I suppose I would say that the vast majority of people are at an onsen for the same reason as you: to clean, relax, and spend time not dwelling on things.

Many people walk around covering their front with a small towel, so feel free to do this too.

It seems like it's quasi-traditional to drink milk after using a public path. It's actually quite good, so maybe there's something to it.

It seems like it's quite common to have a relaxation room where you can sleep, and some places have futons. Obviously, these areas aren't private. You can totally stay overnight in place of a hotel, but you have zero privacy, obviously. The biggest issue with this is that you need to get up to use the public bathroom and might wait a while for an elevator.

There is also a buffet at Toyoso Manyo club, but others have restaurants where you order food. It's quite simple.

You can get a massage, but I didn't do this.

Typically, you wear bathroom slippers in the bathroom so your feet don't get dirty in the bathroom. They will be stationed at the entrance to the bathroom. You only wear these in the bathroom.

Honestly, I would say this is the perfect first-time onsen experience for a foreign otaku visiting Comic Market. It beats the train bath, includes a place to get food, and if you go after Comic Market, the clientele will be mostly otaku who are all feeling similarly tired. It's a great environment to dip your toes into an onsen.

Also, this club in-particular has an open rooftop onsen with relaxation chairs, which is very nice after a long day at Comic Market.

The only problem is that you have to leave afterwards.