A scenic hot spring overlooking the Pacific Ocean, with Kodai no Yu rising from strata dating back about 120 million years
Chiba Choshi City
"Choshi Grand Hotel" is a hot spring hotel in Inubosaki, Choshi City, Chiba Prefecture, with all rooms facing the ocean. Its private source, Kodai no Yu, gushes up from Cretaceous strata 1,300m underground and is a highly saline hot spring with exceptional warming effects. Guests can enjoy it in a rugged, nature-rich rock bath that makes the most of the natural Choshi stone landscape. From the observatory bath in the large public bath, which overlooks the vast Pacific Ocean, you can watch a beautiful sunrise rising from the horizon. The compact dry sauna, where the quiet sound of water creates a soothing atmosphere, and the gentle cold plunge bath using soft underground water are also fully equipped, offering deep relaxation for weary travelers.
TypeNatural Hot Spring
"Kodai no Yu" gushes up from strata about 1,300m underground, dating back about 120 million years to the Cretaceous period. The spring quality is a sodium-chloride highly saline hot spring, with a high salt concentration that warms the body deeply to the core. In a rugged rock bath that makes the most of the natural Choshi stone landscape, you can enjoy a luxurious bathing experience as if melting into nature itself.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity6people
A simple, compact authentic dry sauna located in the large public bath. The quiet two-level L-shaped room is filled with powerful heat, efficiently warming the body and promoting a rich sweat. There is no TV, so you can relax in a meditative atmosphere while listening to the faint sounds of bathwater and the quiet background music inside the hotel. It is ideal for washing away everyday stress and travel fatigue.
Water QualityHot Spring Water
Capacity2people
A cold plunge bath located right near the sauna room. It uses pleasant pumped underground water and is characterized by its soft touch and gentle feel on the skin. The water is not too cold, making it suitable for calmly cooling down a heated body after sauna use. While feeling the open atmosphere of the bath area overlooking the Pacific Ocean, it gently leads you into the steps of totonou.
Closed Days: Open all year
10292 Inubosaki, Choshi City, Chiba 288-0012
Gender Access
Gender Separated
The above applies to the communal (shared) baths. At facilities with private baths or private saunas, guests with tattoos may still be able to bathe. Please check with the facility for details.
Curated by an expert who visits onsen and sauna facilities every day and has explored 300+ locations — only facilities confirmed to be truly exceptional are featured.
Learn moreA scenic hot spring overlooking the Pacific Ocean, with Kodai no Yu rising from strata dating back about 120 million years
Chiba Choshi City
"Choshi Grand Hotel" is a hot spring hotel in Inubosaki, Choshi City, Chiba Prefecture, with all rooms facing the ocean. Its private source, Kodai no Yu, gushes up from Cretaceous strata 1,300m underground and is a highly saline hot spring with exceptional warming effects. Guests can enjoy it in a rugged, nature-rich rock bath that makes the most of the natural Choshi stone landscape. From the observatory bath in the large public bath, which overlooks the vast Pacific Ocean, you can watch a beautiful sunrise rising from the horizon. The compact dry sauna, where the quiet sound of water creates a soothing atmosphere, and the gentle cold plunge bath using soft underground water are also fully equipped, offering deep relaxation for weary travelers.
TypeNatural Hot Spring
"Kodai no Yu" gushes up from strata about 1,300m underground, dating back about 120 million years to the Cretaceous period. The spring quality is a sodium-chloride highly saline hot spring, with a high salt concentration that warms the body deeply to the core. In a rugged rock bath that makes the most of the natural Choshi stone landscape, you can enjoy a luxurious bathing experience as if melting into nature itself.
Sauna TypeDry Sauna
Stove TypeConvection Stove (Sauna Stone)
Capacity6people
A simple, compact authentic dry sauna located in the large public bath. The quiet two-level L-shaped room is filled with powerful heat, efficiently warming the body and promoting a rich sweat. There is no TV, so you can relax in a meditative atmosphere while listening to the faint sounds of bathwater and the quiet background music inside the hotel. It is ideal for washing away everyday stress and travel fatigue.
Water QualityHot Spring Water
Capacity2people
A cold plunge bath located right near the sauna room. It uses pleasant pumped underground water and is characterized by its soft touch and gentle feel on the skin. The water is not too cold, making it suitable for calmly cooling down a heated body after sauna use. While feeling the open atmosphere of the bath area overlooking the Pacific Ocean, it gently leads you into the steps of totonou.
Closed Days: Open all year
10292 Inubosaki, Choshi City, Chiba 288-0012
Gender Access
Gender Separated
The above applies to the communal (shared) baths. At facilities with private baths or private saunas, guests with tattoos may still be able to bathe. Please check with the facility for details.
Curated by an expert who visits onsen and sauna facilities every day and has explored 300+ locations — only facilities confirmed to be truly exceptional are featured.
Learn more