Nomizo Onsen is a natural hot spring located in Sasa, Kimitsu City, Chiba Prefecture. Surrounded by the beautiful landscapes of the Boso Peninsula, it is known for its gensen kakenagashi, meaning that natural spring water flows directly into the bath without being recycled.
Nomizo Onsen is a small hot spring facility located at the entrance to Shimizu Keiryu Park. The only bathing facility is Senju-no-Yu, giving the area a quiet and intimate atmosphere.
Several popular natural attractions are located nearby, including Kameiwa Cave and Nomizo Falls. In particular, photographs showing the cave reflected on the surface of the water in a heart-like shape became widely popular on social media, drawing attention to this part of Kimitsu.
The hot spring uses naturally emerging water from the riverbank of the Sasagawa River. No additional water, recirculation filtration, or disinfection is used, allowing visitors to enjoy a genuine free-flowing natural hot spring.
The spring at Nomizo Onsen is classified as a sodium bicarbonate spring. It is widely known in Japan as a “beauty bath” because of the way the water feels on the skin.
The spring water is said to help soften the skin and wash away old dead skin cells and excess sebum. After bathing, many visitors appreciate the smooth and moisturized feeling of their skin.
The water is also traditionally associated with benefits for skin conditions such as atopic dermatitis, skin irritation, and rough or dry skin.
The bath water has a light amber color, with fine bubbles and brownish mineral deposits known as yunohana. A faint sulfur aroma can be detected, while the water has a slightly salty taste if sampled.
Nomizo Onsen is traditionally said to be beneficial for a variety of conditions, including:
Skin conditions: Skin disorders, atopic dermatitis, heat rash, and dry skin.
Pain and joint problems: Neuralgia, lower back pain, joint pain, and rheumatism.
Injuries: Cuts, burns, and other wounds.
Other conditions: Sensitivity to cold, motor paralysis, and bruises.
Nomizo Onsen has a natural spring flow of approximately 22 liters per minute. Because the amount of spring water is limited, the facility uses a relatively small bathing pool.
A wooden channel is installed around the edge of the bath so that the fresh spring water from the source can be distributed evenly throughout the tub.
The facility also recommends not rinsing off immediately after bathing, allowing the spring water to remain on the skin and providing a longer-lasting hot spring experience.
Large windows in the bathing area provide views of the Sasagawa River valley. Visitors can enjoy the sound of the clear stream, fresh green foliage in spring and summer, and colorful autumn leaves.
At night, the illuminated scenery creates a particularly atmospheric view. Surrounded by nature, the peaceful landscape adds to the relaxing experience of soaking in the hot spring.
A spring-water tap is located near the entrance of the facility, allowing visitors to take some of the natural spring water home.
This unusual service gives visitors an opportunity to enjoy a taste of the hot spring experience even after returning home.
Spring name: Nomizo Onsen Senju-no-Yu
Spring quality: Sodium bicarbonate spring
Source temperature: 15.5°C
pH: 8.63
Natural flow rate: 22 liters per minute
Total mineral content: 805 mg/kg
Shimizu Keiryu Park is a nature-rich park located near Nomizo Onsen. It is home to Kameiwa Cave, which became famous for the heart-shaped reflection created by sunlight and the cave’s reflection on the water under certain conditions.
Nomizo Falls is a beautiful waterfall flowing quietly through the surrounding natural landscape. The peaceful setting makes it a pleasant place to appreciate the scenery and sounds of the forest and stream.
Yoro Valley is a popular nature destination known especially for its beautiful autumn foliage. Walking through the valley during the fall season offers colorful views of the surrounding mountains and forests.
Kameyama Onsen is another hot spring destination in the nearby area. It can be combined with Nomizo Onsen as part of a hot spring-focused trip around southern Kimitsu.
Katakura Dam is surrounded by natural scenery and offers opportunities to enjoy peaceful walks and views of the reservoir.
From Kazusa-Kameyama Station on the JR East Kururi Line, take a taxi to Nomizo Onsen.
From the Kisarazu-Higashi Interchange on the Ken-O Expressway, travel via National Route 410 and Chiba Prefectural Route 24 toward Nomizo Onsen.
Nomizo Onsen is a peaceful retreat where visitors can experience natural hot spring water alongside the beautiful landscapes of the Boso Peninsula.
The free-flowing spring water, tranquil river valley, seasonal foliage, and nearby attractions such as Kameiwa Cave and Nomizo Falls make it an appealing destination for travelers seeking a relaxing experience in rural Chiba.
Whether you visit for a refreshing day trip or combine the hot spring with sightseeing around Kimitsu, Nomizo Onsen offers a chance to slow down and enjoy the natural beauty of the area.