Sanage Onsen is a 100% natural radon hot spring.

Large Bath with Panoramic View (5th floor of Kinsenkaku
- 'Bath of Serenity', 'Sun-dappled Bath')

Sanage Onsen is an all-natural radon hot spring. The breathtaking nature visible from the 5th floor will heal your soul.Known as the "Hot Spring of Health," visitors come from all over Japan to experience its benefits.

  • Large Public Bath
  • Large Public Bath
  • Large Public Bath
  • Large Public Bath
  • Large Public Bath
  • Large Public Bath

Private Outdoor Baths-Gemini (Rejuvenating Bubble Bath)
Sirius (Large Round Bath), Altair (Square Bathtub)

Guests can use once for free. (Advance reservation is not available)
After check-in, please make a reservation using the monitor screen in your room.
Opening hours: 3:30PM to 10:20AM the next day
Usage time limit: 50 minutes

  • Private Outdoor Baths
  • Private Outdoor Baths
  • Private Outdoor Baths
  • Private Outdoor Baths
  • Private Outdoor Baths
  • Private Outdoor Baths
  • Private Outdoor Baths

※Taking advantage of the ceramic tub’s unique heat retention feature combined with natural radon springs, Gemini (Rejuvenating Bubble Bath) warms you from within, massaging and soothing your entire body with millions of bubbles.

※Sirius (Large Round Bath) is our most spacious private outdoor bath. Enjoy a truly intimate and private family gathering.

※Altair (Square Bathtub) allows you to lay flat in the bath, offering ultimate relaxation. On clear nights, cherish a blissful moment gazing at the star-studded sky.

Drinkable Hot Spring Water

All dishes served at the hotel are prepared using this hot spring water.

Properties and benefits of the Sanage hot spring

Benefits of oral consumptionDirectly absorbed through the digestive system, the components of the hot spring exhibit enhanced medicinal benefits on the body.
Benefits of inhalationInhaled through the lungs, the radiation from radon is sent to all parts of the body, enhancing your body’s natural healing and immune system.
Benefits of bathingThe components are slowly absorbed through the pores of the skin and help restore balance to your body.
Applicable conditionsGout, rheumatic disorders, neuralgia, diabetes, gouty diathesis, gastrointestinal disorders, liver disease, cholecystitis, gallstones, stomach ulcers, arteriosclerosis, hypertension, bronchitis, asthma, hay fever, eczema, premature skin aging, constipation, menopausal disorders, chronic gynecological diseases, autonomic dysfunction, neurasthenia, insomnia, post-traumatic sequelae, muscle pain, joint pain, shoulder and back pain, eye fatigue, and more...
Non-applicable conditionsBathing in this hot spring is not recommended for persons with the following symptoms: acute illnesses in general (especially when accompanied by fever), active tuberculosis, malignant tumors, severe heart disease, respiratory failure, renal failure, bleeding disorders, severe anemia, and other progressive diseases.
Changing Rooms
We provide amenities such as a valuables safe box, bath towels, hand towels, toothbrushes, combs, brushes, hair dryers, cleansers (for women), hair tonic (for men)and more in the changing rooms.
Large Public Bath Hours
From 3:00PM to 12:00AM/6:00AM to 9:00AM

Day Trip Hot Spring "Kinsen no Yu"

Only a 2-minute walk from the hotel.
You can also enjoy a day trip and soak at the "Kinsen no Yu” hot spring.

Click here for more details.
  • Day Trip Hot Spring
  • Day Trip Hot Spring

Learn More! What is Sanage Onsen’s natural radon hot spring?

The miraculous hot spring recommended by doctors
It is important to drink clean water to filter out the impurities in the blood that can cause various diseases. There are cancer survivors who continuously drank this spring water. The best hot springs are not only good for bathing but also drinking. While bathing allows the components to be absorbed through the skin, drinking the water allows 100% of the hot spring components to be directly absorbed through the digestive system, resulting in enhanced health benefits.
Sanage Onsen's natural radon hot spring contains radon gas with a concentration of 21.10 mache/76.8 curies, which meets the minimum requirement (8.25 mache) for therapeutic springs. Inhaling it also provides more benefits than bathing in it. Drinking it can help alleviate conditions like gout, digestive disorders, diabetes, and hypertension while bathing in it improves renal function and provides a calming and analgesic effect. It has a wide range of benefits when used for bathing, drinking, and inhalation. Sanage Onsen
Natural Radon Hot Spring and Hormesis Effect
Radon hot springs are a unique type of natural hot spring. The therapeutic effects of radon springs, which account for only 7% of all hot springs in Japan, are attributed to the natural radiation emitted by radon and is called hormesis. This natural radiation works wonders on the human body and poses no harm. The natural radiation absorbed by the body through inhalation, drinking, and bathing activates cells, promotes natural healing, enhances metabolism, and improves immune function throughout the body. It rejuvenates the body and promotes "spontaneous recovery within cells," alleviating various symptoms, so it is ideal for maintaining a healthy body.
The hormesis effect of radon is already being utilized by many physicians in Japan. We invite you to experience the "hormesis effect" of natural radon hot springs for yourself.