River play in an emerald-green mountain stream
About this spot
A valley formed by the Atera River flowing through Okuwa Village in Kiso District, which in 2026 bustles with families from Saturday, July 18 to Sunday, September 6 (on September 12 to 13 and 19 to 23, vehicles are restricted to campground guests). The clarity of the water, shining emerald green, is said to be among the finest in Japan, and the riverside, with pools and shallows in succession, is a perfect setting for river play. Amid nature surrounded by the mountains of Kiso, each member of the family can find their own way to enjoy it, from splashing in the shallows to swimming in slightly deeper pools.
Season & hours
Name: 阿寺渓谷
Date & time: 7/18 (Sat)–9/6 (Sun)・9/12-13・9/19-23はキャンプ場宿泊者以外車両規制。規制期間外は通年アクセス可
Venue: 木曽郡大桑村・阿寺川
Tips
Unlike the snowmelt of the Northern Alps range, this water comes from mountain springs, but it is still chilly even in midsummer, so something to layer on is reassuring. There are slippery spots on rocks and moss, so prepare water shoes. Even outside the restricted period, some stretches of the access road are narrow, so drive with care.
Best time to visit
The sunny hours from just after 1:00 p.m. are recommended, making the cold water easier to play in
Access & map
Okuwa-mura, Kiso-gun · Atera River
Model course featuring this spot
2026 Atera Valley Full-Day Course
Nagano
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