Hello, I am pimlico !
I am Japanese graduate student (art) , currently living in Kyoto.
I am writing this for people who are interested in going to Sento(public bath) in Japan, because there are few rules or manners you should know before you do.
Plus writing in English is good for my English skill too.
Knowing and following rules lead you good Sento experience, so I hope this will be usefull.
Wash your body BEFORE you get in the bath tub
Please wash yourself well before getting into the bath tub.
First thing to do when you get in bath area is that wash your body so that you don't need to worry about making water any dirtier.
Normally there is no shampoo or body soap installed, so you need to bring those or you can buy from the master.
Just ask if they have shampoo for sale. Usually they have small bottle of shampoo and body soap.
NOT wasting water when you shower
Please use the shower with yourself sit in, not standing.
And turn the shower off when you don't use it.
It is obvious in your country, I guess.
Good for environment and for SENTO management.
NO Underwear or Swimsuits
Please take off your underwear before you go into the bath tub .
You don't need to wear swim suits neither.
Just be yourself.
If you have religious reasons to wear something to hide your body, check the master who you paid money normally if you can wear swim suits.
Japanese People don't like putting anything but body into the bath because that make it water not clean.
That's why we don't put towel into the water too (I wrote below).
Keep your towel out of water
Please keep your towel out of the bath tab and water.
We don't put towel into the water when we stay in the water.
It doesn't matter if it is new or used.
That's because putting towel in the water makes water dirtier such as left over soap in towel, or lint , dust etc.
We strongly have common feelings the we SHARE the water, so let the water be clean for people after you .
Don't wash your clothes or underwear
Please refrain from washing your clothes or underwear in Sento.
If you are traveller, you may have clothes you want to wash out.
But SENTO is the place for taking a bath and we share the place.
So use coin laundry shop to do that.
Dry you off BEFORE you go back to the dressing area
Please dry yourself off before coming out to the dressing area.
If you come out wet, you might cause wet floor.
Many older use SENTO so wet floor might give them a cause to fall.
To sum up: Know Bathing Etiquette and Have a good SENTO time
Once you know the manners, it is not hard things to do.
Taking a bath is very good and heals your body.
So if you hesitate to visit SENTO , just learn the manners I wrote above before you go, you don't need to worry about getting trouble.
I hope this would be useful for you.