Terume Ryugu in Osaka Bay: Natural Spring Baths at Sento Prices

Terume Ryugu is a neighbourhood bathhouse in Minato Ward, not a resort spa. Its natural-spring credentials are unusually clear for an Osaka sento: the Osaka Public Bathhouse Association says the source is drawn from around 1,500 metres underground and that the outdoor bath uses free-flowing spring water. The same page only says that some spring water also enters the indoor baths, so it would be inaccurate to describe every tub as free-flowing.

The Sunday schedule is different

The bath is open from 3 p.m. to 11 p.m. on weekdays and Japanese public holidays. Sundays start at 8 a.m.; Thursdays are the regular closing day. That early Sunday opening can work well before a day around Osaka Bay, but it should not be copied into a weekday itinerary.

Adult admission is ¥600, Osaka’s current standard sento fare. The facility lists dry and steam saunas but gives no current surcharge or towel-set price; check the posted rates before using them.

The standard child rates are ¥200 for elementary-school pupils and ¥100 for preschool-age children. A full “arrive empty-handed” set price is not clearly published, so bring a towel or check the counter rather than assuming the sauna or towel is bundled with admission.

What is known about the spring

The source depth and free-flow description apply to the outdoor bath. The association says spring water also flows into some indoor baths, but does not identify the share in each tub or publish a complete breakdown of circulation, heating or dilution. It also does not provide a current source temperature, pH or flow rate on the accessible facility page.

Beyond the spring bath, the listing includes dry and steam saunas, a cold bath and an electric bath. That gives the visit more variety than a single outdoor pool, but the natural-water claim remains specific: the outdoor bath is documented as free-flowing, and some indoor tubs receive source water.

Getting there

Terume Ryugu is about a ten-minute walk from Asashiobashi Station on the Osaka Metro Chuo Line. The Osaka City Bus stop at Minatoharu is around two minutes away, and the association lists eight parking spaces. The address is 2-3-35 Minatoharu in Minato Ward, making it a sensible choice for someone already staying around Asashiobashi or visiting the bay area. From central Osaka, factor in the extra ride and walk rather than treating it as an aquarium-side bath.

For other baths in the same part of the city, see the Konohana and Minato sento guide or compare larger facilities in the Osaka day-use onsen guide.

Fit it into a half-day on the bay

Terume works best when Asashiobashi, Osaka Port or the Tempozan waterfront is already on your route. The Sunday 8 a.m. opening is useful before sightseeing; on other open days, the bath does not start until 3 p.m. Give the station walk about ten minutes each way, or use the Minatoharu bus stop roughly two minutes away. Eight parking spaces make driving possible, not guaranteed at peak times.

The source guide’s editorial scores are comfort 90/100, bath variety 90, cleanliness 70, atmosphere 85, quietness 60, access 80 and value 100. They are not official inspection ratings; the lower access score reflects the walk from Asashiobashi. If your hotel is around Umeda or Tsukamoto and there is no bay-side stop in your day, compare Hikari Nozato instead. Tattoo rules and exact source temperature/pH are not clearly published, so confirm the former with the bathhouse and do not infer the latter.

Sources

Checked: 2026-09-27 - [Osaka Public Bathhouse Association: Terume Ryugu](https://osaka268.com/sento/%E9%BE%8D%E5%AE%AE%E6%B8%A9%E6%B3%89/) - [Osaka Public Bathhouse Association: current standard admission](https://osaka268.com/price/) - [Asashiobashi Station image, Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Osaka_Subway_Asashiobashi_St.jpg) - [Osaka Port Station entrance image, Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Entrance_of_Osakako_Station.jpg) - [Terume Ryugu image, Osaka Public Bathhouse Association](https://osaka268.com/wp/wp-content/uploads/2021/11/160_ryugu03.jpg)

Tags: Osaka onsen, Osaka Bay, Minato Ward, Terume Ryugu, natural hot spring, sento