Looking for the ultimate private getaway? Here are four of the most hidden-away natural hot spring resorts to try. (If you can’t make it out of the city any time soon but still need to de-stress, check out our recommendations for Best Onsen in Tokyo.)

Nanoyado Hotel Iya Onsen

Where: Miyoshi, Tokushima Prefecture

For a truly hidden gem, look no further than Nanoyado Hotel Iya Onsen, located deep in the mountains surrounding the Iya Valley. Here, the natural landscape retains its original wild state with few exceptions of human interference. Find yourself immersed in deep forests, surrounded only by birds singing and the wind blowing through the trees. The view over the valley is unrivalled – even more so because you can enjoy it on your way down to (and up from) the hotel’s outdoor bath, which you get to by cable car. The 170-meter-long ride takes five minutes, giving ample time to take in the sweeping views of Iya Valley and beyond.

Arriving at the baths (there are two – one for men and one for women), guests have an exclusive view over the Iya River from the bath area, which sits on the ridge of the river. The view is stunning both day and night – we recommend going for two dips in one day to fully enjoy the beauty of the region. The 20 rooms available are a mix of Western and Japanese style, some with open-air baths and panoramic views of the valley. Dining options include kaiseki (multi-course) meals or omiki-nabe, a local hot pot dish with a soup base made from miso and local sake. Guests who would like to stop by just for lunch and a bath are welcome, but reservations are required in advance.

For map and contact details, please see our Concierge listing.

Rankeisou Inn

Where: Nagano Sanjo, Niigata Prefecture 

Situated an hour from the nearest train station (there’s a free shuttle bus once a day from Tsubame-Sanjo Station), this historic ryokan sits at the edge of Shinano River, far away from any other houses or inns. Feast on a lavish bounty from the nearby mountains and follow up with a soak in one of the two open-air baths that can be reserved privately. Guests are also welcome to order a traditional sake set, which floats in the bath as you enjoy your dip. In the lobby, you can drink straight from the ryokan’s pure, natural hot spring.

For map and contact details, please see our Concierge listing.

Takaragawa Onsen Osenkaku

Where: Minakami, Gunma Prefecture

Historians have found evidence that this hot spring area was used by people in the Jomon period (14,000-300 BCE) of ancient Japan, but the ryokan itself dates back to the Taisho era (1912-1926). Ideal for couples who want to spend some quality time together, this rare resort doesn’t just have one mixed-bathing open-air bath – it has three! Mixed bathing areas require guests to be nude, but women are provided with a special towel to wrap themselves in before they take a dip. All baths look out onto the river, offering breathtaking views in every season. Staff at the hotel are warm and most speak at least two languages.

For map and contact details, please see our Concierge listing.

Hoshi Onsen Chojukan

Where: Minakami, Gunma Prefecture 

This ryokan has a 140-year history and is registered as a National Tangible Cultural Property. Located inside Joshinetsu-Kogen National Park, it’s protected by the shade of trees in summer, making it the perfect place to escape the summer heat. The Hoshi no Yu bathhouse, constructed in a typical Meiji period style, has mixed bathing facilities for the brave. Choyu no Onsen is for women only and sits adjacent to a nearby stream, offering a beautiful vista of the flowing water and forest surrounding it. Dropping in for lunch and a bath is permitted, but make sure to reserve in advance.

For map and contact details, please see our Concierge listing.