A sento (銭湯) is a Japanese public bathhouse — distinct from an onsen (natural hot spring) in that the water is heated tap water, not mineral spring water. But sento are an essential piece of local daily life: neighborhood bathhouses where people go not just to bathe but to relax, socialize, and decompress. Visiting one is one of the most authentic non-tourist experiences you can have in Japan.
Sento vs. Onsen
Sento: Heated tap water (sometimes with added minerals or bath additives), neighborhood-scale, typically ¥400–¥550 entry, frequented by locals, no accommodation. Onsen: Natural geothermal spring water with certified mineral content, often attached to a ryokan or resort, ¥500–¥2,000+ for day use. Both share the same bathing etiquette. Some facilities brand themselves as "super sento" — large, resort-style facilities with multiple baths, saunas, and restaurants, closer to onsen experience at sento prices.
The Bathing Rules (Non-Negotiable)
1. Shower before entering the bath — wash your entire body at the individual shower stations (provided: shampoo, conditioner, soap). This is mandatory, not optional. 2. No towel in the bath — your small towel stays outside or on your head; it does not enter the water. 3. No swimwear — Japanese baths are nude. This surprises many first-time visitors. 4. Keep hair up — long hair should be tied up or clipped to avoid touching the water. 5. No phones or cameras — none, ever, anywhere in the changing room or bath area. 6. Tattoo policy — many sento prohibit visible tattoos (rules vary; small or covered tattoos are often overlooked; ask before entering).
What to Bring
Essential: small tenugui (hand towel) or purchase one at the counter. Optional: your own shampoo/soap (usually provided but you may prefer your own). Locker fee: usually ¥10–¥20 coin deposit, returned. Most sento sell soap, razors, and toiletries at reception. Pay at the entrance, receive a locker key, change in the gender-separated changing room, and proceed.
The Sento Experience
A typical sento has: a main hot bath (main pool, ~42°C), a cold bath (water bath, ~17°C — alternating hot and cold is excellent for circulation), a sauna (often additional fee, ¥200–¥500), and individual shower stations. Alternate between hot and cold 3–5 times for the classic "totonoi" (settled/meditative) state. Stay as long as you like — 45–90 minutes is typical. The changing room usually has hair dryers, skincare products for purchase, and sometimes a rest area with vending machines.
Best Sento Experiences in Tokyo
Daikoku-yu (Katsushika): Beautiful Edo-style architecture, famous Mt. Fuji mural (a sento tradition), no tourists, deeply authentic. Shimizu-yu (Minami-Aoyama): Design-forward renovation in a fashionable neighborhood — a "new wave" sento drawing younger visitors. Koganeyu (Kinshicho): Award-winning renovation, gallery space combined with traditional bath, excellent sauna. Thermae-yu (Shinjuku): Super sento format near Shinjuku Station — accessible, high quality, natural hot spring water bused from out of town. ¥2,200 entry.