Beyond Japan's onsen: Discovering Asan, Korea’s historic hot spring capital

The open-air baths at Paradise Spa Dogo offer a relaxing soak amid the winter air in Asan, South Chungcheong Province. Courtesy of Paradise Spa Dogo

It is 4:30 a.m. The streetlights are barely flickering, and the winter sun is hours away from rising. Yet, a queue is forming in the darkness.

These people are not waiting for a limited-edition sneaker drop or a new iPhone. Clutched in their hands are plastic baskets filled with toiletries. They are waiting for the "first water" — the pristine, untouched draw of the hot spring that opens at 5 a.m.

"People who are serious about water always show up this early," a ticket booth attendant said.

This is a daily ritual in the Oncheon District of Asan, South Chungcheong Province. Often called the "City of Hot Springs," Asan offers a Korean alternative to Japan's onsen experience. The city features three distinct hot spring zones located within short driving distances of each other: the historic Onyang, the therapeutic Dogo, and the modern Asan.

Here is a guide to the three unique styles of Asan’s thermal waters.

Visitors queue up before opening time at Sincheon-tang in the Onyang Hot Spring district, Asan, South Chungcheong Province. Korea Times photo by Lee Han-ho

Onyang: The King’s spa

Onyang Hot Spring is the oldest recorded hot spring in Korea. According to the Samguksagi (History of the Three Kingdoms), the Baekje Kingdom referred to this area as Tangjeong (Hot Spring Well) as early as 18 A.D.

During the Joseon Dynasty (1392–1910), it solidified its reputation as a royal retreat. King Sejong the Great, suffering from eye ailments, visited frequently the area and built a temporary palace known as the Onyang Haenggung. King Sejo, plagued by skin diseases, called the waters a "Divine Well," while King Seongjong erected a monument to honor its healing properties.

Although the original palace was destroyed during Japanese invasions in the 16th century, the site was later restored by King Hyeonjong, ensuring its legacy as a royal retreat.

Modern bathhouses began to appear during the Japanese colonial era (1910–45), originally built to cater to Japanese settlers. Following Korea's liberation, the area evolved into a premier domestic retreat, hitting its peak in the 1970s as the nation's top honeymoon destination.

Visitors enjoy a soak at Paradise Spa Dogo in Asan, South Chungcheong Province. Korea Times photo by Choi Heung-soo

While it is no longer the glamorous destination it once was, Onyang remains a powerhouse in the industry. It is currently the second-most visited hot spring district in Korea, drawing 4.25 million visitors in 2024. It trails only Bugok Hot Spring in South Gyeongsang Province (4.68 million); together, they are the only two sites in the country to surpass the 4-million mark.

The flagship establishment is Sincheon-tang, which opened in 1960. Unlike modern resorts, Sincheon-tang operates as a traditional bathhouse, pumping water directly from four source wells. While the surrounding streets look aged, the interior is renovated and pristine, featuring Hinoki tubs and acupressure waterfalls.

The water here is scalding. The average temperature is 49.5 degrees Celsius (121 degrees Fahrenheit), with some tubs reaching 60 degrees Celsius. It is an alkaline spring (pH 7.7–9.0) rich in sodium bicarbonate, known for treating neuralgia, arthritis, and skin conditions.

The spa opens from 5 a.m. to 6 p.m., with early morning being the peak time for purists. The entry fee is a modest 10,000 won ($7.15), dropping to 8,000 won for seniors.

An acupressure waterfall cascades from an artificial rock wall inside Sincheon-tang. Korea Times photo by Lee Han-ho

Dogo: The healing sulfur spa

Located about 11 kilometers west of Onyang, Dogo Hot Spring is famous for its therapeutic reputation. Legend has it that monks from seven nearby temples achieved enlightenment here, giving the area the name Dogo (high spiritual attainment). A local myth also claims the water has cured blindness and healed deep wounds.

Unlike Onyang’s scalding heat, Dogo’s water averages a cooler 28.8 degrees Celsius but is prized for its rich sulfur and silica content.

Although a Japanese developer first attempted to tap the spring during the colonial era, technological limitations at the time delayed commercialization. It wasn't until the 1970s that proper facilities were established. Thanks to the rarity of sulfur springs in Korea, Dogo quickly rose to fame, spearheading Asan’s golden age of tourism alongside Onyang.

Steam rising from the hot springs freezes onto trees and rocks, creating a winter landscape near the lazy river at Paradise Spa Dogo. Korea Times file

The centerpiece is Paradise Spa Dogo. Standing on the site of the former Paradise Dogo Hotel, this facility blends a water park with traditional bathing. It features massage areas, saunas, and extensive open-air pools.

In winter, the outdoor spa is the highlight. Bathers can soak in grape, peach, and mugwort-infused tubs heated to over 40 degrees Celsius while steam rises into the freezing air. The private Hinoki tubs, tucked away in a secluded corner, are particularly popular for photos.

Trees covered in hoarfrost stand next to the infinity pool at Paradise Spa Dogo. Korea Times photo by Lee Han-ho

While the water slides operate only in summer, the wave pool runs year-round. Though it looks small, the 1.8-meter depth creates surprisingly strong swells.

Paradise Spa Dogo is one of only nine facilities in the country designated as a "hot spring resort." Certified by the Interior Ministry for its superior water quality and therapeutic environment, the spa taps a premium source at 35.1 degrees Celsius — about 6 to 7 degrees warmer than the local average.

Bathers relax in the outdoor lazy river at Paradise Spa Dogo in Asan, South Chungcheong Province. Korea Times photo by Lee Han-ho

Asan: The forest retreat

Asan Hot Spring is the youngest of the trio, with its first source discovered only in 1989. Designated as a tourist zone in 1991, it quickly emerged as a modern resort destination.

Its defining characteristic is its location. While Onyang sits in the city center and Dogo lies in the open plains, Asan Hot Spring is nestled at the foot of Mount Geumsan (251 meters). Bathers in the outdoor tubs can gaze out at the surrounding forest, enjoying both a thermal soak and a forest bath simultaneously.

Steam rises from the bubbling outdoor thermal pool at Asan Spavis. Korea Times photo by Lee Han-ho

The water, pumped from 200 meters underground, is near-neutral (pH 7.1–7.6) with an average temperature of 27.7 degrees Celsius. It is widely considered the "softest" water among the three districts. The area is compact, with just two major facilities sharing four source wells.

Asan Spavis pioneered the "hot spring water park" concept in the region upon opening in 2002. While its massive outdoor attractions — including a 75-meter wave pool and 125-meter slide — are closed in winter, the facility remains a top draw for cold-weather visitors.

Winter guests flock to the indoor "bade pool" — a hydrotherapy zone equipped with high-pressure massage jets — as well as the outdoor thermal pools and the main bathhouse. The bathhouse is architecturally distinct, featuring a glass pyramid on the ceiling that lets natural sunlight flood the steam-filled hall. The beam of light cutting through the mist creates a dramatic, airy atmosphere that brings the outdoors in.

The main indoor bathhouse at Asan Spavis features a high glass ceiling, allowing natural sunlight to fill the space. Korea Times photo by Lee Han-ho

This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by a generative AI system and edited by The Korea Times.