Private onsen?

Do you know any onsen located in Tokyo or Osaka where I can have privacy taking bath in the hot spring?or at least with my family?Is it required to remove all your? Can't we use a swimsuit?
Thank you in advance

I can't help you with any private onsens/sentos, but I can say having just done my first trip to Japan, the naked thing honestly isn't an issue. I was expecting it to be bad, but I wandered into the locker room and saw a dozen naked guys of all shapes/sizes/ages and figured I should just jump in head first, figuratively speaking. Even as the only westerner there, nobody cared and nobody (that I noticed) stared. And I can assure you, I'm one of nature's less perfect specimens of humanity.

I was far more worried about breaking some sort of etiquette rather than being naked around strangers. Going to an onsen is a great experience, especially when it's cold outside, and I think it would be a shame to miss out just because you're worried about nudity. When in Japan, do as the Japanese do!

In regular onsen, it is required to remove all clothes EXCEPT some onsen (usually outdoor, often mixed) will allow women especially to wear a large towel to cover themselves. If you want to have the onsen experience but are shy and wont compromise, I suggest finding one of these, such as Takaragawa in Minakami, Gunma (http://www.gunmajet.net/travel/takaragawa-mixed-onsen-by-laura-roberts...). I'm sure there are others nearer to Tokyo, but this particular one I have been to and can recommend.

Otherwise, for private onsen, you can rent out at a number of places, and the fancier ones sometimes give you access to a private one if you rent a room. In these cases it is still technically required to remove all clothing, but I guess since it is private no one would know the difference.

Many people have asked this, so please do a search on the forum for results and check those threads: http://www.japan-guide.com/search/?cx=015609760794546757367%3A7rvvvope...

Thank you all. Guess, I'll try as both of you said!!