１. Kawayu Onsen Sennin-buro, Wakayama  (川湯温泉　仙人風呂【和歌山県】)

 

As the name Kawayu (川湯）indicates, this hot spring flows from the river. The water temperature is rather hot so it's best to mix with cool stream of the river to make it comfortable enough to bathe in.  Usage will be restricted when the water level increases due to rain. The bathing area alongside the river  is wide with a makeshift changing area, where you can change into your bathing suit. Open from December to late February.  Admission free.   

Kawayu, Motomiya-cho, Tanabe-shi, Wakaya 

２．Kinugawa Nioson Plaza, Tochigi (鬼怒川仁王尊プラザ【栃木県】)

 

This outdoor spa is close to Nikko and an ideal pit stop for a day trip. There are 3 open-air baths, including a pleasure boat-shaped tub.  You can wear swimsuits in one of them which is for mixed bathing. It's called Butai no Yu (舞台の湯)  and overlooks the stream of Kinugawa River. You can watch the sightseeing boats floating down the river as you soak in the hot tub.  Entrance fee: 700 yen for adults.

371-1 Kinugawa Onsen Ohara, Nikko-shi, Tochigi

３．Izu Shimoda Seiryuso, Shizuoka (伊豆下田　清流荘【静岡県】)

 

This inn has outdoor heated pool using natural hot spring water.  The water used is directly from the hot spring source and change almost the entire gallon every night. This inn is quite remarkable in retaining abundant amount of naturally sourced spring water . You can also use many other authentic outdoor hot spa within the premises but you aren't permitted to wear swimsuits in them. In addition, the place is not for a day use- you need to be the guest staying at the inn.

2-2 Kouchi, Shimoda-shi, Shizuoka

４．Beppu Suginoi Hotel HANA, Oita (別府　杉乃井ホテルHANA【大分県】)

It's a prominent hotel in Beppu Onsen, one of the acclaimed spa towns in Japan. The view from the outdoor spa nicknamed "Terraced Riced Fields (棚田)" is magnificent. You can wear your swimsuit to dip in.  Cutting across the changing room from this spa, there is Aqua Garden on the other side of the wing where you can also enter by wearing your bathing suit. The view of the coastline is as beautiful as that from Infinity Pool of Marina Bay Sands in Singapore.   Entrance fee: 1500 yen for adults on weekdays.

1 Kankaiji, Beppu-shi, Oita

５. Oedo Onsen Monogatari Mangekyo, Chiba (大江戸温泉物語　万華郷【千葉県】)

Oedo Onsen Monogatari in Odaiba is a popular spot among oversesas tourists. This branch in Urayasu is not only great because of its location (close proximity to Tokyo Disneyland) but also you can dip in the outdoor hot spring (yes, a hot bath, not a swimming pools) with family or friends by wearing swimsuits. Because it isn't a pool, usage of swimming rings are prohibited.

7-3-12 Hinode, Urayasu-shi, Chiba

６．Kitayuzawa Onsen Yumoto Daini Meisui-tei, Hokkaido (北湯沢温泉　湯元第二名水亭【北海道】)

This hot spring inn in Hokkaido has a vast  man-made onsen beach. You can of course wear swimsuit for a dip. Recreational facilities with hot spring pools are generally western-style, but this is an authentic Japanese ryokan.  Obviously you can't have a tropical beach with Japanese settings but it has a lovely atmosphere surrounded by Japanese-style walls. There are also genuine, traditional outdoor hot baths where wearing bathing suits are prohibited. Entrance fee: 800 yen for adults.

 300-7 Kitayuzawa Onsen-cho, Otaki-ku, Date-shi, Hokkaido

７. Shin-Hodaka Onsen Shinzansou, Gifu (新穂高温泉　深山荘【岐阜県】)

 

This isn't a typical swimming pool-type outdoor baths that are normally for onsen-goers wearing bathing suits, but it's a mixed bathing spot situated along Gamada River, conserving natural settings.  Towards the upper stream of the river you can oversee a magnificent view of Mount Nuketo with height of 2813 meters and beyond that, the terrain of North Alps.  The area becomes lovely covered with red leaves in fall and snow in winter.  Entrance fee: 500 yen for adults.

Okuhida Onsengo,  Takayama-shi, Gifu

８. Yuashisu Togo Ryuhoukaku, Tottori (ゆアシス東郷龍鳳閣【鳥取県】)

 

There is Hawai (no joke but it's pronounced as "Hawaii") Beach in Tottori and Togo Onsen is located just nearby. This multi-purpose hot spa facility is facing Lake Togo and the neighboring site is a large-scaled Chinese-style garden named  Enchoen. The site of Ryuhoukaku also has a Chinese influence and depicts the famous hot spring in China, Huaqing Pool. Watching the sun set from the outdoor bath is simply stunning. Entrance fee: 870 yen for adults.

560-7 Hikiji, Yurihama-cho, Touhaku-gun, Tottori　

９．Hokkaido Hakodate Mizunashi Kaihin Onsen, Hokkaido (北海道函館　水無海浜温泉【北海道】)

 

This hot spring is located at Esan-misaki , 50 km east of Hakodate. The hot spring streams out from the seabed. You can't access when the tide is high so make sure you check the tide times before paying a visit. And if you prefer your water temperature hot, try to be there soon after the low tides. The site will sink under the sea a couple of hours after that. There are separate changing areas for men and women. It's open 4 hours in total - a couple of hours each, before and after the low tide.   Admission free.

Esanmisaki-cho, Hakodate-shi, Hokkaido

１０．Shin-Hodaka Onsen Shin-Hodaka no Yu, Gifu (新穂高温泉　新穂高の湯【岐阜県】)

 

This is one of the famous drop-in bathing spots in Shin-Hodaka Onsen area. It's a large mixed bathing place next to Gamada River, surrounded by stones and with a direct view from the bridge over it. You can change into your swimsuit at a rather primitive changing area, but wearing them is optional.  The entry is free yet there is a donation box at the entrance.  We recommend 200 to 300 yen as gratuity for keeping the place clean and pleasant.    

Kansaka, Okuhida Onsen-go, Takayama-shi, Gifu 

１１．Shiriyaki Onsen, Gunma (尻焼温泉【群馬県】)

The hot spring streams from the bottom of the river. You can bathe anywhere and anyway you like in the area, but in other words, there is no control mechanism so you need to bathe at your own risk in the wild, rustic environment.  Plus, you have to find the spot for hot stream at your discretion, but simply dig the area and the spring will well up.  Most people wear bathing suits yet there is no changing room. Legend has it that people with problems around their buttocks got cured by soaking in the warm river water, hence the name Shiriyaki (尻焼) literally means 'burning bottoms'. Admission free. 

Iriyama, Nakanojo-machi, Agatsuma-gun, Gunma

１２. Kamuiwakkayu no Taki, Hokkaido (カムイワッカ湯の滝【北海道】)

 

This is one of the best kept hot springs of Shiretoko. There is an access point from the forest path to make your way alongside the gently steep water falls. The surface is rather slippery, so do wear sandals with swimsuits and some waterproof garments. There are small basins of waterfalls on the way but walk on.  Eventually there is a large pool on a steep hill and that is your final destination. It is a shallow pool with luke warm natural spring water.  Entry is prohibited during winter. Admission free.

Shari-cho, Shari-gun, Shiretoko Natural Park, Hokkaido