Kanagawa Kawasaki City
Asahiduyu Gensen Yuiru
Kawasaki's sacred sauna spot, proud of its highly concentrated natural hot spring and amber cold plunge bath that allows diving
- Natural Hot Spring
- Free-flow from source
- Aufguss available
- Auto löyly available
- Aroma löyly available
- Finnish sauna
About Asahiduyu Gensen Yuiru
"Asahiduyu Gensen Yuiru" is a day-use sauna and hot spring facility in Kawasaki City, Kanagawa Prefecture. It was the first in Kawasaki Ward to take on deep drilling to 1,200 meters underground, and struck a highly concentrated natural therapeutic spring whose mineral content is more than 25 times the standard level. Its biggest hallmark is the commitment to serving that spring water unheated and chlorine-free, flowing continuously from the source. With two sauna rooms—a high-temperature löyly sauna and a medium-temperature sauna dedicated to aufguss—it hosts aufguss sessions every hour by heat-wave performers. It also offers an amber-colored cold plunge bath with a diving depth of up to 150 cm, as well as an ultra-strong carbonated spring with more than 1500 ppm, earning a reputation as one of Kawasaki's most iconic sauna destinations.
Hot SpringONSEN
Kawasaki Asahiduyu Hot Spring
A nationally rare, highly concentrated natural therapeutic spring created by the first deep drilling attempt in Kawasaki Ward, reaching 1,200 meters underground. The total mineral content of the spring water reaches 25,800 mg, boasting an exceptional concentration more than 25 times the general hot spring standard of 1,000 mg. Such high concentration is classified as a hypertonic spring, meaning the minerals are more easily absorbed into the body. Because the source water is served unheated and chlorine-free in free flow from the source, guests can enjoy the freshness of the components and the original bathing sensation to the fullest. The water is amber-colored, and its hue changes depending on the light during the day and at night. After bathing, the body stays warm for a long time, making the strong heat-retaining effect clearly noticeable.
Amber Non-Perceptible Highly Carbonated Spring
So intensely fizzy that it is also called Wilkinson carbonated spring, it envelops the whole body in countless bubbles when you enter the amber-colored well water, creating the sensation of being inside a carbonated drink. The temperature is around 30°C, within the non-perceptible temperature zone, so at first it feels cool, but circulation gradually improves and the sensation changes into a unique warmth that spreads gently from within. They also hold a regular event called Fresh Fruit Carbonated Spring, in which large amounts of fresh fruit are added, making it a popular program where you can enjoy different scents and carbonated bathing experiences each season.
SaunaSAUNA
Löyly Sauna
Its most striking feature is the overwhelming volume of steam created by the combination of a sauna stove made by Technorisecom, designed specifically for löyly, and Fuji lava stones rich in iron and minerals. During the auto-löyly at 15 and 45 minutes past each hour, about 500 ml of water is sprayed at once, causing high-temperature steam to erupt explosively throughout the sauna room. On the top tier, an intensely scorching environment forms in an instant. The three-tier bench layout and the silent, quiet-bathing design create a sharp contrast with the roar of steam. The high heat efficiency, achieved by stacking a large number of sauna stones, produces a steam volume far beyond that of ordinary saunas.
Aufguss Sauna
A sauna room designed specifically for the aufguss experience. With a high ceiling and three-tier bench seating that allows 5 to 6 people per level, it provides a spacious environment that balances openness and a sense of togetherness. Two HARVIA tower stoves perform automatic löyly every 20 minutes, and a heat-wave performer conducts aufguss once an hour. Each session offers a different high-entertainment presentation combining program, music, and aroma, so there is always something new to look forward to, no matter how many times you visit.
Cold BathCOLD BATH
Amber Diving Cold Plunge Bath
The defining feature is the ability to dive into the deepest part while enjoying continuously flowing amber-colored well water pumped up from underground in Kawasaki Ward. The tub has a two-level structure, 120 cm and 150 cm, divided by a handrail, with a route designed so you can first acclimate in the shallower side before diving into the deepest section at 150 cm. The water is cold, and a strong current constantly cools the skin, making the perceived temperature feel even sharper. As the name suggests, this is a rare cold plunge bath in Japan where diving all the way under your head is officially allowed, and the sense of liberation the moment you fully submerge after thoroughly sweating is unmatched. The well water also contains a small amount of hot spring minerals, giving it a smooth, soft feel.
Where to stay near Asahiduyu Gensen Yuiru
Hotels and ryokan we feature, within 10 km in a straight line.
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Facility Information
- Address
- 3-1-2 Kokan-dori, Kawasaki Ward, Kawasaki City, Kanagawa Prefecture
- Business Hours
- Monday11:00〜00:00Tuesday11:00〜00:00Wednesday11:00〜00:00Thursday11:00〜00:00Friday11:00〜00:00Saturday10:00〜00:00Sunday10:00〜00:00Holiday10:00〜00:00
Irregular Holidays
- Closed Days
- Irregular Holidays
- Gender Access
- Gender Separated
- Tattoo Policy (Communal Bath)
- No Tattoos
- Official Website
- View official site
Access
By car
- About 4 minutes from Asada IC toward Yokohama
- About 3 minutes from Hamakawasaki IC toward Tokyo
By train and bus
- JR Kawasaki Station East Exit, Platform 5 → Rinko Bus Route Kawasaki 24 (Kokan Loop) → Get off at Rinko Junior High School Mae
Parking available. As the surrounding area is residential, please be considerate of pedestrians and noise. From the Rinko Junior High School Mae bus stop, cross the pedestrian bridge and the building
Visited by the Editor-in-Chief
The Editor-in-Chief visited in person in February 2026
The Ultimate Cold Plunge Bath Is Right Here
Read the full review
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