Niji no yu

Day Use

Yes

10:00–23:59

Last entry is at 23:15 (close at 24:00). The bathhouse stays open through the New Year holidays with no closures.

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

Jet bath and electric bath are described as separate from the outdoor (露天) route in the same review.

SaunaYes

Dry heat sauna room

Cold BathYes

Cold water plunge bath, typically used after sauna

Policies & Services

KidsWith Conditions

Welcomes children and families

Children of elementary-school age or younger must be accompanied by an adult; unaccompanied use is refused.

DiningYes

Restaurant or dining open to visitors (not just hotel meal plans)

WashingYes

Shower, wash stations, soap and shampoo provided

TowelsYes

Towels available to rent or borrow

Rest AreaYes

Relaxation space for after bathing

A rest area exists but reviewers describe it as small with limited seating.

虹の湯温泉二色の浜店

Niji-no-yu Onsen Nishiki-no-hama

Operated by · 株式会社ALLURE

湯

Simple

Color: faintly yellow and clear
Taste: almost tasteless
Odor: odorless

Sodium-Calcium Bicarbonate spring

pH 7.4NeutralHigh silica

Composition fingerprint0.3 g/kg dissolved · Hypotonic

Na⁺61

Ca²⁺29

HCO₃⁻93

◀ CationsAnions ▶

Sodium Na⁺: salt's cation — pairs with chloride to make the water salty.
Bicarbonate HCO₃⁻: "soda" — softens skin, leaves it smooth.

Known good for

Smooth skindry, rough skin
Recoveryfatigue, stress

A lightly mineralized simple thermal spring. The wellhead measures 29.7 °C, putting it in the low-temperature class — the bath water is reheated before serving. Neutral pH (7.4) and a faint yellow tint give a gentle, unassuming character, while a meaningful 60.8 mg/kg of metasilicic acid leaves the skin slightly smoother than the modest mineralization would suggest.

Sampled at wellhead·Analyzed May 29, 2024·株式会社総合水研究所·Cert no. SP240010

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