When we decided to do a Tokyo side trip, we wanted to do three things - Snow Monkeys, Sumo Tournament, and Tsukiji market .... unfortunately, the fish market was closed. As the song goes - 2 out of 3 ain't bad.
The Snow Monkeys!
I started searching for tours and couldn't find any for the day we wanted. Changed the search wording to private tours - Boom! we were locked in.
The Snow Monkeys we saw are located at Jigokudani Yaen-Koen in the Joshinetsu-Kojen National Park. It's about 35 kms from Nagano. Here is a link to the website
JIGOKUDANI YAEN-KOEN|Welcome , Japanese Monkey to the world it has a couple of excellent web cams.
The tour company we selected was Snow Monkey Resorts
Welcome to SNOW MONKEY RESORTS! | Nagano, Japan They were very good to deal with and delivered exactly what they promised - no problem recommending this firm. There are many tour options - we selected this one
SNOW MONKEY PRIVATE TOURS | SNOW MONKEY RESORTS and tacked on Zenko-ji Temple
Given we were only staying 4 nights in Tokyo we did this as a day trip however, you could easily stay a few days in the area and do many other activities. Once we booked the tour - I had to sort out transport from Tokyo > Nagano > Tokyo ... as mentioned upthread we purchased JR East rail pass. It did the trick, but it would be excellent if you could purchase a pass that included Tokyo Metro.
It's a full day, as the advice was it was best to start the tour at 8.45am, meeting at Nagano station... the tour ended when we were dropped off at the station to catch the 5.09pm Shinkansen back to Tokyo. We caught a taxi from the hotel at 6.30am and caught the 7.20am Shinkansen. Just like clockwork we arrived at Nagano at 8.43am where our guide was waiting.
I'm happy to answer any questions.