Oarai, Ibaraki
Shiosai-no-Yu
A convenient choice for a self-drive day around Oarai Beach, seafood spots and the Pacific-facing outdoor bath. The hot spring is a strong saline spring; the high-concentration carbonated bath is artificial, not another natural spring pool. Tattoos are not allowed.
Check before bathing
- Opening hours
- 10:00–21:30; last admission 20:30. Adult admission is ¥1,000 on weekdays, ¥1,200 on weekends and public holidays, and ¥1,400 on special holidays. Generally open year-round from April 2026, with occasional unscheduled closures.
- Tattoo policy
- People with tattoos are not admitted.
Spring & water temperature
- Spring-source temperature
- Not published.
- Bathing temperature
- Not published.
- Spring source
- Oarai Sun Beach Onsen.
- Spring classification
- Strong sodium-chloride spring, described by the operator as fossil seawater.
- pH
- Not published.
- Flow rate
- Not published.
- Water handling
- The operator identifies the men's and women's panoramic outdoor baths and jet-bubble bath as natural hot spring pools. The high-concentration carbonated bath is artificially made by dissolving carbon dioxide; pool-by-pool dilution, heating, circulation and disinfection details are not fully published.
Older tourism listings show lower prices and a regular third-Thursday closure; the current operator information takes precedence.
How to read a bath profile
Spring-source temperature and actual bathing temperature are kept separate. Each score is shown independently for comparison rather than collapsed into one overall score.
