In any case, don't worry. Japanese women tend not to be that large in the chest, and a group of women is hardly going to ridicule you/stare because you have small breasts!

But what Sira is saying is that you can't take a "bath towel" to the bathing room. On the other hand, you are supposed to bring along a face towel (a thin towel about 2 feet long). Most women press the towel lightly in front of her so that it will sort of hide the front part of her body when walking around.

Btw, the towel should be used to scrub yourself with soap before dipping into the tub. While in the tub, the towel should be kept either at the rim of the tub or on your head (you shouldn't soak it in the tub). Then when going back to the dressing room, you should wipe yourself roughly with that towel.

This is for way up north. But there are some mixed-sex onsens where you must wear a towel over your bits.

I think it spoils the point but I guess it depends on the onsen. And also, don't worry about coming into close contact with a guy because although there are mixed onsens, they are sometimes segregated by an imaginery line.

But these places are rare all thanks to the government who imposed extra taxes on the onsens for keeping this traditional mixed bathing option. So, most of the onsens converted to single sex. As was their plan.

You can still find them up north. I know that their are some in Miyagi and Fukushima. But a long way for a bath. But worth it if your in the area.

I use this website for onsen research. It lets you know everything from water pH to cost. It even lists if a swim suit is allowed.

http://www.secret-japan.com/onsen/

Then click on the "Search" link at the top of the screen.

Hope this helps

Adam

I've just checked the site. I'm guessing that your staying in Tokyo. There are 3 listed onsens that allow swimsuits in Tokyo-to.

Hamanoyo (Oshima)
http://www.secret-japan.com/onsen/show.php?&selcode=131

Ashitsuki (Shikinejima)
http://www.secret-japan.com/onsen/show.php?&selcode=47

Jinta (Shikinejima)
http://www.secret-japan.com/onsen/show.php?&selcode=48

I've not read the reviews, so leave that to you. But they are listed averaged as 3-4 star out of 5). I don't know where they are in relation to central Tokyo. Might be a bit of a train ride. Maybe someone else could let her know.

If your not in Tokyo. Try searching the lists at
http://www.secret-japan.com/onsen/search/search.php

Hope this helps