Kotan Onsen Hot Spring

Although the picturesque hot spring location with its stunning views of Kussharo lake and swans was somewhat marred by a large group of loud tourists, the scenery itself was still breathtaking. Even without the hot spring, it was a pleasure to see the beautiful lake and its inhabitants. For those looking for a more peaceful experience, it may be worth considering visiting during a quieter time or exploring other hot spring options in the area. Nonetheless, the natural beauty of the location made it a memorable experience overall.

Enjoyed the onsen after a strenuous hike. The pool was clean, the temperature was warm and in wonderful condition to enjoy the sunset in it. Not really visible from the street. Really comfy and highly recommended.

I visited in the 3rd week of June 2023. It was afternn and there was no one in a 50m radius. The water temperature was comfortably hot. I wanted to take a quick soak. But the water was filled with algae/mold.
I came in the winter 5 yrs ago. It was much better with more to experience and see. Such as the birds and snow.

Very beautiful and serene. Lake covered with ice in the winter. There is a small open public hot spring by the shore.

There was one other person when we arrived, but most of the time we had the onsen to ourselves. Very hot! 38-43°C. Amazing to sit in the hot water while there are still chunks of ice floating on the other side of the rocks, and the view is stunning.

When you arrive there are two small changing rooms on each side with sliding doors, one for men and one for women. You can change into swimsuits and leave your bags there, they are in view of the onsen. Definitely worth a visit, we made a detour from our drive to Lake Masshu for a 15 minute dip.

Just happened to come upon this place after a long day of traveling.
What an amazing experience!!!
Was hesitant to dip in but since no one is around, I gathered my guts to get in, thinking this is my first and probably not going to happen for a long time. Also set my mind in thinking that who ever see me here doesn’t know me 😅So I let myself be warmed and get the relaxation of a lifetime by this fascinating and stunning hot spring ☺
Experience at it’s finest only in Japan 🇯🇵

屈斜路古丹
Kotan retenburo is no doubt best visited winter time. We visited twice , the first time experienced a moment perfect , snowing heavily while soaking in the onsen watching the beautiful lake and surrounded by many good-looking swans staring at us curiously.

Excellent free, mixed onsen on the edge of Lake Kussharo. It is managed by the local town. It's not so big, but it was clean. There is a small shed to change your clothes, but no privacy. Bathing suits are allowed or you can go nude.

Incredible outdoor onsen right on the lake. It's a little small and not much gender separation, but the view is absolutely worth stopping for.

It's a must must must visit site if you are in eastern Hokkaido during winter time, words cannot describe how amazing the panaromic view is ... Self drive is highly preferred, there are bus service but there are only 3-4 trips in a day

This is the most beautiful onsen that we visited on our entire 17 day trip to Japan. It was particularly beautiful during sunset.

It is outdoor and right next to a big lake, so there were mosquitos in the evening - be prepared!

Best of 3 free lake side onsens on lake kusharoko.
Its also the smallest so easy to get full

This is one of the best free onsen spots in Japan:) It’s made and been maintained by local volunteers. Onsen temperature is very good and there is even a changing room.
It’s closed once every month for cleaning.
You can wear a bathing suit but here is Japan and Japanese people are all naked in the onsen.

Nice little open onsen built by local ppl. Onsen just next to the following house and near to the lake.

Once in a life time experience. So beautiful. So comfortable too.

A very very beautiful small hot spring with white swans around you.

Excellent. Dozens of Whooper Swans!

Beautiful outdoor onsen. Just besides the lake.

This beautiful spot was one of my favourites in the Teshikaga area. The open-air onsen was a perfect place to relax while enjoying the breathtaking view of Lake Kussharo. The bath is split into male and female sides but you still need a bathing suit or at least a towel to wrap yourself in. If you're visiting in the summer, you can also swim in the lake before warming up in the onsen.

Get naked and jump right in. The most open onsen with the nicest view.