Visiting the Snow Monkey Park from Kyoto or Osaka
Why the geography does not work
Everything about reaching Jigokudani is built around Nagano Station, and Nagano sits on the Hokuriku Shinkansen line out of Tokyo and Ueno, roughly 80 to 110 minutes from the capital. From Kansai you are crossing the country first and then doing the whole Nagano approach afterwards: the bus or the Dentetsu line out to Kanbayashi Onsen, then 1.6 km on foot, 30 to 35 minutes each way. The last part is the same for everyone, and it does not shrink because you started further away.
What I would actually do
Move the monkeys to the Tokyo half of your itinerary. Almost every Japan trip touches Tokyo at one end, and from there the day is a known quantity, laid out on getting there from Tokyo. If your route genuinely only passes through Kansai, then plan a night in Nagano city, Yudanaka or Shibu Onsen and go up in the morning. Trying to do it and get back to Kyoto the same day turns a good visit into a travel day with a monkey in the middle.
If the reason for going is the photograph, check the month before you rearrange an itinerary for it. The bathing is a winter behaviour, so a summer detour from Kansai is a very long way to go for macaques beside a river.
The Kyoto alternative
Kyoto has its own Japanese macaques at Arashiyama Monkey Park Iwatayama, a hillside troop with a view over the city and a steep climb of its own. There is no hot spring and no bathing, so it is not the same experience, but it is a genuinely good couple of hours and it is already on your doorstep. The comparison, and the question of how many snow monkey parks Japan actually has, is on snow monkey parks in Japan.
If you are going anyway
Give it two days rather than one, sleep near the trailhead, and go up at opening. That turns the worst version of this trip into the best one. The timings are on how long to spend.
Frequently asked questions
Can you visit the snow monkeys from Kyoto?
Only as an overnight, realistically. Nagano is far closer to Tokyo than to Osaka, and the park is a further bus ride plus a 1.6 km walk beyond Nagano Station. The Tokyo routing is on getting there from Tokyo.
Are there snow monkeys near Osaka?
Not the bathing ones. The closest macaque park to Kansai is Arashiyama Monkey Park Iwatayama in Kyoto, which is a hillside troop with a city view and no hot spring — the differences are on snow monkey parks in Japan.
How long does it take from Kyoto to the Snow Monkey Park?
Long enough that I would not attempt it and return the same day. Plan a night in Nagano city, Yudanaka or Shibu Onsen and walk up in the morning — see how long to spend for the shape of the day once you are there.