Thermae-yu Shinjuku

What to expect

Thermae-yu is a large 24-hour bath and sauna complex at 1-1-2 Kabukicho, on the edge of Shinjuku’s nightlife district. It is the kind of place Japanese people call a super sento or spa land: you pay once, change into the lounge wear they hand you, and move between baths, saunas, a restaurant and recliners for as long as your ticket lasts. It is not a traditional onsen inn and does not try to look like one.

Inside there are separate men’s and women’s bathing areas, each with a run of baths at different temperatures, saunas and a cold plunge. Beyond the baths you will find a restaurant and café, a relaxation lounge with recliners and couch sofas, massage and beauty treatments, a stone sauna room, and a rooftop sports bar and fitness area. The whole building is non-smoking apart from designated smoking rooms, and e-cigarettes count.

Is it real onsen water?

This is the question most visitors ask, and the honest answer is: one bath, yes, with heavy treatment.

The outdoor bath, Kamiyo no Yu, uses natural hot spring water from the Kamiyo no Yu source in Naka-Izu, on the Izu Peninsula in Shizuoka. The water is carried to Shinjuku by road, not piped from under the building. The operator lists it as a sodium-calcium sulfate spring, hypotonic, alkaline and high-temperature at source, with a pH of 9.0. It also says that, to keep the water in good condition, it is heated, topped up with water, and recirculated through filtration and disinfection. So this is real hot spring water by Japanese standards, but it is not fresh-flowing source water.

Every other bath is ordinary or specialty water, not onsen:

• Carbonated bath: about 1,100 ppm of carbon dioxide, 100-102°F38-39°C.
• Silk bath and white bath (shirayu): about 108°F42°C.
• Reclining bath and jet bath: about 104°F40°C.
• Neutral electrolysed water bath: about 104°F40°C, on both sides.
• Lotion bath (women only): water mixed with skin lotion, about pH 5.
• Cold plunge: about 63°F17°C.

Saunas run at about 194°F90°C on the men’s side and 185°F85°C on the women’s side. Men also get a mist sauna at about 122°F50°C, and women a salt and mud-pack sauna at about 109°F43°C.

Prices and booking

Prices are from the operator’s guide in October 2026, tax included.

Ticket	Members	Non-members
Monday to Thursday, up to 18 hours (6:00-24:00)	¥2,900	¥3,100
Friday to Sunday, holidays, special days, days before holidays	¥3,000	¥3,200
Late-night surcharge, Monday to Thursday	+¥1,800	+¥2,000
Late-night surcharge, other days	+¥2,100	+¥2,300

The late-night surcharge applies if you are inside at any time between midnight and 6:00, and it extends your stay to 24 hours from entry. Go past 24 hours and you pay another day’s admission. You cannot leave and come back on the same ticket.

The entry fee includes the ¥150 bathing tax, lounge wear and a towel set, so you can arrive empty-handed. The stone sauna room (ganbanyoku), open 12:00-24:00, costs ¥900 extra. Women get ¥100 off through a running campaign, and ¥200 off on Wednesdays (except the last Wednesday of the month). An 11-visit book costs ¥29,000. The spa takes cash, credit cards, transit IC cards, PayPay, Alipay and several other e-money services. No booking is needed.

At check-in you get a wristband. Its four-digit number is your locker, which you open by tapping the band on a reader. Lounge wear and towels are handed out at the counter in front of the lockers. Outside food and drink are not allowed.

Rules and etiquette

Bathe naked in the baths, as in any Japanese bathhouse, and wash before getting in. The stone sauna room is split by sex under a Shinjuku ward ordinance.

The tattoo rules are stricter than at many newer spas. Anyone with tattoos, irezumi or body art of any size is refused by default. Japanese men, and foreign men who live in Japan, cannot enter even if they cover up. Overseas tourists can bathe if they show a passport or plane ticket and wear one of the spa’s own tattoo stickers (¥330 each); the operator’s notice ties this to an entry stamp less than 90 days old. Women, Japanese or foreign, can enter with fashion tattoos on a trial basis; any single tattoo larger than 30 by 30 cm must be covered with a sticker.

The spa also turns away anyone who is drunk, unwell, or has a skin condition or possible infectious illness. Guests aged 13 to 17 need photo ID and a guardian and must leave by 20:00.

Getting there

• Shinjuku-sanchome Station (Marunouchi, Fukutoshin and Toei Shinjuku lines): Exit E1, about 2 minutes on foot.
• Shinjuku Station (JR, Keio, Odakyu): East Exit, about 9 minutes on foot.
• Higashi-Shinjuku Station (Fukutoshin and Oedo lines): Exit A1, about 9 minutes.
• Seibu-Shinjuku Station is also close, and the operator posts a walking map.

There is a small on-site car park with size limits, at ¥1,000 for up to 6 hours, rising to ¥8,000 for 18-24 hours. In October 2026 the spa was offering bathers up to 6 hours free there for a limited period. Call 03-5285-1726 before driving in.

When to go

Weekday mornings and early afternoons are the quietest. Evenings and weekends are busier, and Friday to Sunday tickets cost more. The bath areas close in turn for cleaning in the small hours, from 3:00 to 6:00 on the 2nd-floor bath.

Where to stay nearby

Thermae-yu has no guest rooms, but with the late-night surcharge you can stay through the night in the lounge. For a proper bed, Shinjuku has a wide choice of hotels within walking distance. For real source water within reach of Tokyo, try Tenzan Tojikyo or Hakone Yuryo, both near Hakone-Yumoto, which you can reach from Shinjuku on the Odakyu line.

Safety notes

• Hot and cold: going from a 194°F90°C sauna to a 63°F17°C plunge is a strain on the heart. Take it slowly and rest between rounds.
• Alcohol: there is a bar on the roof. Do not bathe or use the saunas after drinking.
• Night stays: keep your wristband on and your locker shut; the operator is not responsible for lost keys.