How do you photograph people naked in a hot springs? That's a question I get asked all the time. Actually, I lie. I've never been asked, but I often get asked a similar question which is - how do you get access to things to photograph.
Just ask. Sounds simple doesn't it? And often it really is that simple. Particularly with people photography I find that the majority of people are really happy to be photographed, many of them thrilled at the idea.
A good place to start is before you go, contact the tourism bureau of the country you're travelling to. You can't just call them up and ask for places to photograph, it's best to do some research yourself and when you've found something that you think would be really interesting to see, ask if they might know someone who you could talk to.
The other way to do it is when you get there. For example at a hot springs, you're most likely not going to be allowed in with a camera to start shooting, and even an email in advance might not get you permission. So when you arrive you need to speak to somebody at the hotel. Usually I talk to the marketing person first. They'll usually have the best idea of where and when would be good, and they want the hotel to be seen in the best light obviously so they'll make sure the place looks spick and span.
Of course the other way you can do it, if you're in a place that's not very crowded, is to ask one of your fellow guests, who you've been plying with beer all night, if they'd mind being photographed with a yellow towel on their head. Promise them you won't show any naughty bits and you're sure to get a positive response.
I just promised the above gentleman that I'd bring his daughter and grandkids home every couple of years to say hello. I cheated a little - this is my famous father-in-law again. I was on a magazine assignment to photograph the national parks of Hokkaido (a dream assignment!) and took the whole family along. This was taken in a little private 'minshuku' - a traditional Japanese inn and we were the only ones staying there. I really loved this outside bath but the only other man in the whole place was you-know-who. So after dinner down we went for a bath and a photo session.
It was quite dark in there and I had 100 ISO film in the camera so I had the camera on a tripod. It's a very wide angle lens (20mm if I remember rightly) to fit everything in in what was a very small space. Even though I could have made a brighter photo I deliberately kept it quite dark to show the dim conditions that we were in.