A Complete Guide to the 4 Must-Visit Hot Springs in Oita Prefecture !  CITY SPA Satisfies Your "Outdoor Nude Desire"

▲ The spring water in Beppu City, Oita Prefecture, forms a beautiful scene of rising white steam.

Reported and photographed by Yan Yuncen / Oita Prefecture, Japan

Oita Prefecture, located in the northeastern part of Kyushu, boasts the highest volume of hot spring water discharge and the greatest number of hot spring sources in Japan. It is not only extremely popular among Japanese people, but also enjoys high recognition in Taiwan. When you visit Oita, don’t miss these 4 hot springs — some nestled atop high-rise buildings, others hidden in wild streams. Just grab your towel, shed your bathrobe, and enjoy the pleasure of soaking whether in an outdoor bath or indoor facility.

1. CITY SPA Sky

▲ At CITY SPA Sky, you can soak nude while overlooking Oita City.

If you’re tired from exploring the city and want to relax in a hot spring, “CITY SPA Sky” is your best bet. Blossom Oita, which opened in April 2015, has specially designated floors 19 to 21 as a hot spring area. Aside from being free for hotel guests, it’s also available to general tourists for just ¥1,900.

▲ A view of a room at Blossom Oita hotel.

Floors 19 of CITY SPA feature sauna and salt baths, while floor 20 is arranged with vanity areas and indoor baths. After taking the elevator to floor 20, visitors can access separate male and female changing rooms, follow the staff’s guidance to lock their clothes in lockers, and then head out with just a small towel — ready to go “nude.”

The open-air bath on floor 21 features a constant temperature of 42°C “natural hot spring” and a 38°C “high-concentration carbonated spring.” Since the carbonated spring is clear and transparent,the operator thoughtfully provides female guests with a fully black, button-up “modesty cloth,” while men have to go all-natural. However, the men’s and women’s baths are separated by a wooden wall about one floor high, so there’s no need to worry about being seen.

▲ Night view from the café on floor 20 of CITY SPA Sky.

Floor 21 of CITY SPA offers the best scenery in all of Oita. Soaking at night not only lets you see the lights of the city, but also gaze out over Beppu Bay. If you want to indulge that long-suppressed “high-altitude nudity desire,” this is the perfect spot for an evening soak.

2. Yufuin’s “Shimoyu”

▲ Shimoyu is Yufuin’s oldest open-air bath.

When visiting Yufuin, aside from getting lost amid Japan’s most beautiful streets and quirky shops like the Snoopy Café, you definitely shouldn’t miss Kinrin Lake. The bottom of Kinrin Lake is traversed by hot spring water, and in the early winter mornings, steam condenses on the lake’s surface. When sunlight hits it, it looks like fish scales — hence the name. By the lakeside lies an unassuming thatched hut, which is the location of “Shimoyu.”

▲ A corner of Kinrin Lake.

Unlike the expensive hot spring resorts in Yufuin, Shimoyu is a public bath that has existed since the area’s early days. It serves the general public, and entry costs just ¥100, which you drop into a bamboo tube at the entrance. Inside, there are two square tubs, but there are no clear signs indicating which is for men or women. The changing area is merely separated by a bamboo screen, and there’s always a risk of an accidental exposure.

▲ Yufuin’s famous Snoopy Café.

Setting aside its ultra-“open” public nature, Shimoyu is actually not inferior to typical hot spring hotels. It has everything from washbasins to stools. While soaking in the hot spring, you can also enjoy views of green bamboo, which helps soothe eye fatigue.

Shimoyu is open daily from 8 AM to 10:30 PM. If you want to enjoy great-quality hot spring water on a budget without risking being seen, try coming early to secure a spot. If you’re lucky, you might even catch a glimpse of the famous lake mist while passing by Kinrin Lake.

3. Yumoto Onsen (Yutakayu)

▲ Street view of Yumoto Onsen.

Remember the scene from Spirited Away with the red lanterns hanging outside the bathhouse? “Yumoto Onsen,” located in the same town of Yufuin (Yufuin Town) as Yufuin Onsen, has perfectly recreated the movie setting. Along a 300-meter stone-paved slope, strings of lanterns bearing the name “Yumoto Onsen” hang between the buildings. When the sun sets and the lanterns light up, it feels as if you’ve stepped into a Studio Ghibli film.

▲ Public hot spring baths at Yumoto Onsen, divided into male and female sections.

Yumoto Onsen is situated along the Hanamagino River and was one of the most famous hot springs in Japan during the Taisho era (1912–1926), attracting up to 400,000 visitors a year. But as the nearby Yufuin gained popularity, Yumoto gradually declined. By 2015, domestic visitor numbers had dropped to just 50,000, with very few foreign tourists.

However, compared to the commercialization of Yufuin, Yumoto Onsen offers a sense of retro charm. The wooden inns built along the stream preserve the architectural style of the Taisho period, with buildings not exceeding three stories. No matter which inn you stay in, you can fall asleep to the sound of the rushing Hanamagino River.

▲ The grilled wagyu beef at Yumoto Onsen’s “Tsuruya” inn is absolutely exceptional.

The stone-paved streets also provide great backdrops for photos. Most of the ryokan in Yumoto offer free or paid yukata rental services. Just change into a yukata, put on some geta, step onto the street, and snap a photo — you’ll capture a vintage aesthetic. If you’re looking for a quiet place to relax in a hot spring, Yumoto Onsen is definitely a great choice.

4. Nagayu Onsen

▲ The Marblesoda Onsen Hall is renowned for its high-concentration carbonated hot springs.

Nagayu Onsen is located on the eastern foothills of the Kuju Mountain Range and has been famous since the Edo period (17th–19th century) for its exclusive hot springs developed by the local daimyo. In addition to the long-established carbonated spring "Omae-yu," there is also the natural hot spring "Kani-yu" in the Serikawa gorge, and the high-concentration carbonated spring "Marblesoda Onsen Hall," allowing visitors to enjoy multiple experiences in one day.

"Omae-yu" is a famous hot spring that has been passed down since the Edo period. According to the "Kyushu Tourism Promotion Organization," this spring is "effective to drink? effective to bathe? a tonic for the heart, stomach, and intestines," and is one of Japan’s rare carbonated hot springs. The hot spring facility is located on the basement level, separated from the Serikawa River by just a wooden screen. During the rainy season when the river swells, visitors can even enjoy the contrast of hot and cold sensations.

▲ A corner of Omae-yu.

"Kani-yu" is located by the Serikawa River and is said to have been formed when a lecherous monk was struck by lightning after failing to woo a local maiden. It is an open-air mixed-gender bath where visitors can only change clothes under a bridge and then bury themselves in the hot spring along the red brick path. Although Japanese onsen culture typically requires nudity, Kani-yu is in such an exposed location that visitors are allowed to enter wrapped in a towel.

▲ Kani-yu, nearly submerged by a swollen river, with only its eyes visible.

The "Marblesoda Onsen Hall" is a 5–10 minute walk from Kani-yu. With over 1,000 grams of carbon dioxide gas per liter, as soon as you enter the bath, tiny bubbles cover your entire body. Thanks to its circulation-boosting effects and year-round water temperature of around 38°C, even those who don’t usually soak in hot springs can easily try it. After bathing, your skin feels smooth and silky without being sticky, leaving you feeling refreshed overall.

▲ Generous beef cuisine at Nagayu Onsen’s Daimaru Ryokan.

To meet the needs of travelers from central and southern Japan and to save them the trouble of transferring in Fukuoka, Mandarin Airlines has launched a new twice-weekly direct flight from Taichung to Oita starting September 15. Operated by an E190 aircraft with 104 seats, the flight takes just over two hours, offering hot spring enthusiasts a brand-new travel option.