Far from just a quick soak in the tub, onsen (hot springs) have long been part of Japan’s natural and cultural landscape. Every year millions of people make their way to famous onsen retreats, spend their vacation at onsen resorts or simply stop by their local onsen to unwind and chat with friends.

As defined by the Onsen Law in 1948, onsen have to use spring water that has a temperature of 25 degrees or more and are also required to have certain levels of natural elements. The history of the steaming streams stretches back a long way — Matsuyama’s renowned Dogo Onsen is mentioned in the classical Japanese history text Nihon Shoki in 720.

During the tumultuous Sengoku Period, in the 15th and 16th centuries, samurai would utilize the restorative effects of onsen water to heal wounds. But the natural hot springs were not often used by everyday folk; it wasn’t until the Edo Period (1603-1868) that onsen became more accessible.

Today, visiting onsen has become a national pastime. There are more than 3,000 hot spring destinations, from the more traditional, to quirky and unusual — some have even been known to mix red wine and coffee into their water. There’s a lot of choice, so we’ve highlighted some of the more distinctive onsen in Japan.

quirkiest onsen shikaribetsu

1. Lake Shikaribetsu Onsen, Hokkaido

When winter approaches, the wilds of Japan’s north are caked in snow. One place that knows how to make the most of the freezing temperatures is Lake Shikaribetsu Onsen. Situated within Hokkaido’s sprawling Daisetsuzan National Park, this onsen is particularly special. When temperatures drop low enough, the waters of Lake Shikaribetsu freeze and an onsen is created on the solid surface.

Carved out of snow and ice, the onsen sits surrounded by mountains on what is Hokkaido’s most elevated lake. Needless to say, it’s breathtakingly cold in winter, but the onsen is a steamy 40 degrees — more than enough to keep toasty. Even the changing rooms are made out of ice and there’s an ice bar to enjoy a refreshing post-onsen tipple. Make sure to go when it’s cold. Come spring, the ice melts and the lake onsen disappears for another year.

2. Nishiyama Onsen Keiunkan, Yamanashi

If it’s history you’re after then you’ll find it at Nishiyama Onsen Keiunkan. The hot spring hotel was founded in 705 and was officially recognized as the oldest hotel in the world in 2011 by Guinness World Records.

Nestled among the slopes of Japan’s Southern Alps in Yamanashi Prefecture, the inn has sourced the water for its onsen from the nearby Hakuho Springs since it first opened its doors over 1,300 years ago; it has even been run by the same family for a whopping 52 generations.

The hotel offers a traditional ryokan (Japanese inn) experience with the option to bathe in one of its four open-air baths and two indoor baths tucked away in a peaceful ravine. Staying in such storied history comes at a cost, however, with prices around ¥50,000 per night.

quirkiest hot springs yunesun hakone

3. The Hakone Kowakien Yunessun, Kanagawa

Fans of red wine take note: This is the onsen for you. More quirky than relaxing, Hakone Kowakien Yunessun, Kanagawa Prefecture, bills itself as a “hot springs amusement park.”

The resort has a variety of specialized pools to try out. The red wine pool, for example, involves actual red wine being poured into the pool by a sommelier, with oversized wine bottles and barrels adding to the boozy ambience.

Elsewhere, coffee enthusiasts can spend time floating in the brown waters of a coffee-infused onsen, or there’s also a green tea pool for the more health conscious. With a total of 26 baths to choose from, being bored is not an option.

4. Kuronagi Onsen Ryokan, Toyama

Far off the beaten track, Kuronagi Onsen Ryokan can be found enveloped in the remote forests of the Kurobe Gorge, Toyama Prefecture. Going off grid and bathing in the seclusion of the mountains is the name of the game during a stay at this ryokan, and the only way to reach it is via the charming Kurobe Gorge Railway.

On arrival, expect to be completely cut off from the outside world. There’s no phone signal, no Wi-Fi and no television. Instead of checking social media or replying to emails, guests can fully relax in the sizable mixed-gender, open-air baths on the banks of the winding river, soundtracked by the gentle trickle of water and birdsong. Zero distractions.

quirkiest onsen hirauchi kaichu

5. Hirauchi Kaichu Onsen, Kagoshima

Down in Kyushu, just off the coast of Kagoshima Prefecture, the subtropical island of Yakushima is rich in natural wonders; the island’s ancient evergreen forests, a UNESCO World Heritage Site, provided the inspiration for Hayao Miyazaki’s 1997 film Princess Mononoke. It’s also here that you’ll find some distinctive coastal onsen.

On the island’s southern shore, the Hirauchi Kaichu Onsen is made up of rocky, open-air pools that fill from below with hot spring water — the catch is they’re only accessible twice a day at low tide. The unmanned mixed-gender baths are run on an honor payment system; ¥200 goes towards upkeep and guarantees you a serene soak by the sea while waves crash on the shore around you.

Want more unusual onsen recommendations? Check out this article.

This article was published in Tokyo Weekender’s special issue, Made in Japan. Flip through the issue by clicking on the image below.