Ashiyasu Onsen Iwazonokan

I visited this day spa just before lunch on a Saturday and tried both the open-air rock bath and indoor bath. The hot spring runs a little cool, so you can soak for a long time. The showers use hot spring water too, which felt gentle on my skin rather than like chlorinated tap water. The changing rooms are separate, so I'd bring a tracksuit to make changing easier.

The Oiwa open-air bath is my favorite here. It's spacious, and soaking while looking up at the stars is lovely. The water is warm near the spring source and gets gradually lukewarm farther away, so I'd choose a summer stay over winter. The staff are all friendly and easy to talk to. I visited during the November holidays and the autumn leaves were beautiful. It seems several celebrities have stayed here, and there are photos on display. I was especially glad to spot an illustration by a certain manga artist.

Set in Ashiyasu Onsen, this inn has its own hot spring source. The grounds are split between a main building and an east building, and the main one has a real Showa-era feel. The sodium-calcium sulfate water is 43 degrees with a pH of 9.4, and it flows freely. Around the spout, the deposits harden like snow. The inn appeared in the original story of the anime "Zatsu Tabi," which aired in spring 2025, and there's a signature from author Kenta Ishizaka on display. There's no elevator, so keep that in mind if mobility is an issue. The quiet setting and good food made for a relaxing stay.

[First visit in May 2025] I stopped here as part of a hot spring tour. The water is a freely flowing NaCa sulfate spring. The outdoor bath, said to be the best part, was under construction that day, so only the indoor bath was open. That was a real disappointment. Admission was 800 yen. I'd like to come back to try the outdoor bath. 😎