Sun Lupinus in Shintomi: A Rail-Friendly Hot Spring with an Iodine-Rich Profile
Sun Lupinus is a public bath seven minutes from Hyuga-Shintomi Station. Entry is ¥500; see its iodine-bearing spring, outdoor bath and sauna.
Checked: September 27, 2026
Sun Lupinus is refreshingly easy to plan: a local day-bath facility, a short walk from a rail station, with a ¥500 adult admission. The spring itself is more distinctive than the building. Its analysis identifies an iodine-bearing sodium-calcium chloride spring, high in dissolved minerals and nearly 20.3 grams per kilogram in total dissolved matter.
The spring is the reason to come
The facility’s posted analysis dates to February 2, 2023. It lists a source temperature of 54°C and pH 7.4, with iodine ions at 43.6 mg/kg and total dissolved matter of 20.281 g/kg. Those figures describe the spring analysis, not the temperature of the bathing pools. The operator describes the baths as source-fed and flow-through; there is no need to add an unsupported claim about every pool’s individual heating or treatment settings.
The public bath has an indoor bath, an outdoor bath, a far-infrared sauna, a cold bath and outdoor chairs for cooling down. The footbath is currently suspended. It is a compact public facility rather than a sprawling super-sento, so the appeal is the mineral spring and an easy soak, not a long list of themed pools.
Current hours, admission and what to bring
| Detail | Current listing |
|---|---|
| Hours | 10 a.m.–10 p.m.; last admission 9:30 p.m. |
| Regular closing day | Third Monday; moves to Tuesday when Monday is a public holiday |
| Adult admission | ¥500 |
| Elementary- and middle-school students | ¥300 |
| Preschool children | Free |
| Towel purchase | ¥350 |
Body soap, shampoo, conditioner and hair dryers are provided. Bringing your own towel keeps the visit simple.
The town’s facility has a sauna, cold bath and a small rest room; the rest room is for bath users and closes at 9:45 p.m. The sauna is available until 9:30 p.m. Children aged eight and older cannot bathe with an opposite-sex guardian under the local public-bath rule.
The station walk is a genuine advantage
Hyuga-Shintomi Station is about seven minutes on foot, making this easier to reach without a rental car than many rural onsen. Trains on the line are not frequent, so check the timetable before committing to a return departure. By car, the centre is about 40 minutes from Miyazaki City or the airport, and parking is available.
The bath closed temporarily earlier in 2026 after equipment problems, but the operator announced repairs complete and reopened on August 1. Its website still posts monthly closing-day notices, so check the latest notice if visiting on a holiday week. For a wider look at nearby public baths, see the Saito–Koyu day-onsen guide; it compares different facilities rather than repeating Sun Lupinus’s spring profile.
