Onsen vs Sento: What's the Difference and How to Use Both

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Onsen vs Sento: The Real Difference

A sento entrance with noren curtains. 男 (otoko) = men, 女 (onna) = women. Some swap sides daily — check the kanji, not the color.

The difference is simpler than most guides make it sound:

	Onsen (温泉)	Sento (銭湯)
Water	Natural hot spring water (geothermally heated, mineral-rich)	Heated tap water (sometimes with added minerals or bath salts)
Legal definition	Must meet specific mineral/temperature criteria under Japan’s Hot Spring Law (温泉法)	Any public bath open to the public
Price	¥1,000–¥3,000+ (no regulation)	¥520 in Tokyo (price set by the Metropolitan Government, 2024)
Location	Resort areas, some urban facilities	Every neighborhood in Tokyo
Vibe	Relaxation destination, full-day experience	Quick daily ritual, 30–60 min
Tattoo policy	Often banned	Generally more relaxed
Extras	Rotenburo (outdoor bath), multiple spring types, restaurants	Basic baths, sometimes sauna

Then there’s “super sento” (スーパー銭湯) — large commercial facilities that blend both concepts. Chains like Raku Spa (ラクスパ), Oedo Onsen Monogatari (大江戸温泉物語), and Thermae-Yu (テルマー湯, Shinjuku) offer multiple baths, saunas, restaurants, and rest areas for ¥800–¥2,500.

Which Should You Try First?

Start with a neighborhood sento. Here’s why:

• ¥520 vs ¥2,000+. If you mess up etiquette (you won’t, but still), you’ve lost ¥520, not ¥2,500.
• Sento regulars are often older locals who’ve seen everything. They’re patient with beginners.
• The core experience — stripping down, washing, soaking — is identical. The water source doesn’t change the ritual.
• Many renovated Tokyo sento are genuinely beautiful (not the dingy stereotype you might imagine).

For our full onsen deep dive (specific springs, ryokan etiquette, mixed-gender baths), see the complete onsen guide.

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How to Use a Sento or Onsen — Step by Step

Step 1: Enter and Pay

At a sento:

• Look for the noren curtain (暖簾) hanging over the entrance
• Pay at the bandai (番台, front counter) or a ticket machine (券売機)
• Tokyo sento: ¥520. Some charge extra for sauna (¥200–¥400)
• Say: “Otona hitori” (大人一人 — “One adult”)

At an onsen facility:

• Pay at the front desk or ticket machine
• You’ll usually get a locker key and sometimes a rental towel set

What to say at the counter:

• “Taoru wa arimasu ka?” (タオルはありますか？ — “Do you have towels?”)
• “Te-bura desu” (手ぶらです — “I came empty-handed”) — staff will set you up with everything

Step 2: Find the Right Entrance

Look for the kanji:

• 男 (otoko) or 男湯 = Men’s bath
• 女 (onna) or 女湯 = Women’s bath

Some sento swap the men’s and women’s sides daily. Read the kanji, not the curtain color. Getting this wrong is extremely embarrassing.

Step 3: Undress Completely

In the changing room (脱衣所, datsuijo):

1. Remove all clothing — swimsuits are not worn in Japanese baths
2. Place belongings in a locker or basket
3. Take only a small towel (hand-towel sized) into the bathing area
4. Leave your large towel in the changing room

This is the part that intimidates most first-timers. Everyone is naked. Nobody is looking at you. After 30 seconds, it feels completely normal.

Step 4: Wash Your Body — THE Most Important Step

This is where sento and onsen etiquette overlap completely, and where beginners fail:

1. Find an empty washing station (洗い場, araiba) — a low stool with a shower head and mirror
2. Sit on the stool (don’t stand)
3. Rinse your body with warm water
4. Soap up and scrub everything — hair, face, body. Thoroughly.
5. Rinse all soap off completely
6. Then — and only then — you may enter the bath

Why this matters: The bath water is shared by everyone. Entering without washing is the single biggest taboo. Japanese bathers will be visibly uncomfortable if you skip this step.

Washing stations at a sento. Sit on the stool, scrub with soap, rinse completely — then enter the bath.

Step 5: Enter the Bath

1. Enter slowly. The water is hot — typically 40–44°C (104–111°F).
2. Don’t submerge your towel. Fold it on your head or place it on the bath edge. Putting a towel in shared water is a faux pas.
3. Don’t swim, splash, or make noise. This is a place of quiet relaxation.
4. Soak for 10–15 minutes. If you feel dizzy, get out — the heat is real.

If the sento has multiple baths, try them in order:

• Start with the warmest tub (main bath)
• Try the rotenburo (露天風呂, outdoor bath) if available
• Sauna → then cold plunge (水風呂, mizu-buro) for the brave
• Electric bath (電気風呂, denki-buro) — a mild electric current runs through the water. Weird sensation, surprisingly popular. Start slow.

Step 6: Dry Off Before Returning

Before stepping back into the changing room:

1. Wring out your small towel
2. Wipe down your body so you don’t drip water onto the changing room floor
3. Then enter the changing room and dry off with your large towel

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The Tattoo Question

This is the #1 concern for foreign visitors. Here’s the reality:

Onsen (Resort Facilities)

Many onsen ban tattoos. The ban originated from associations with yakuza (organized crime). Signs will say “入れ墨・タトゥーのある方はご遠慮ください” (People with tattoos, please refrain).

Workarounds:

• Tattoo cover patches (タトゥーカバーシール) sold at pharmacies and convenience stores. Cover small tattoos with these skin-colored bandages.
• Private onsen (貸切風呂, kashikiri-buro) at ryokan — rent a bath for yourself. Usually ¥2,000–¥5,000 per hour.
• Some resort onsen are relaxing policies as tourism grows, but don’t count on it.

Sento (Neighborhood Bathhouses)

Sento are generally more relaxed about tattoos. Many neighborhood sento don’t mention tattoos at all. The regulars have seen everything, and the “no tattoo” rule is less strictly enforced.

That said, a few things to know:

• No guarantee. Some sento do post “no tattoo” signs.
• Call ahead: “Tatū wa daijōbu desu ka?” (タトゥーは大丈夫ですか？ — “Are tattoos okay?”)
• Smaller, older neighborhood sento are generally more accepting than large commercial facilities.

Known Tattoo-Friendly Sento in Tokyo

• Matsumoto-yu (松本湯, Nakano) — clean, modern, explicitly tattoo-friendly
• Koganeyu (黄金湯, Sumida) — architect-renovated, stylish
• Kairyo-yu (改良湯, Shibuya) — modern design, relaxed atmosphere

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What to Bring (And What You Don’t Need)

Item	Bring It?	Notes
Small towel	Optional — ¥50–¥200 rental at most sento	Used in the bathing area
Large towel	Optional — ¥100–¥300 rental	For drying off
Shampoo/soap	Optional — most sento provide these free	Some budget sento don’t — check
Coins (¥520+)	Yes	Many sento are cash-only
Swimsuit	No — never worn in Japanese baths	Leave it at the hotel
Phone	Leave in locker	Photography is strictly prohibited

Bottom line: You can walk into any sento with nothing but ¥700 in coins and walk out refreshed. Everything you need is available.

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After the Bath: The Milk Ritual

This is non-negotiable Japanese culture: after bathing, you drink cold milk (牛乳, gyūnyū) or coffee milk (コーヒー牛乳, kōhī gyūnyū) from a glass bottle while standing in the changing area.

Most sento have a vending machine stocked with:

• Meiji milk — the classic (¥130–¥160)
• Coffee milk — sweet, addictive (¥130–¥160)
• Fruit milk (フルーツ牛乳) — strawberry or banana flavored

You drink it with one hand on your hip, head tilted back. This isn’t a joke — it’s genuinely what people do. Try it once and you’ll understand why.

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Finding a Sento Near You

• Tokyo Sento Association website: 1010.or.jp — full list with addresses
• 東京銭湯マップ app — iOS and Android, map-based sento finder
• Google Maps: Search “銭湯” (sentō) near your location

Tokyo still has 440+ active sento as of 2025 (down from a peak of 2,600+ in the 1960s). They’re disappearing as owners retire without successors — visiting them now is both a cultural experience and an act of preservation.

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FAQ

Q: Can men and women bathe together?

A: Not at sento or standard onsen. All baths are gender-separated. The exception is konyoku (混浴, mixed-gender) baths, found at some rural hot springs — not in Tokyo. Private rentable baths (貸切風呂) at ryokan allow couples/families.

Q: Is there a time limit?

A: No formal limit at sento, but 60–90 minutes is typical. Don’t camp out. At super sento/onsen facilities with rest areas, you can stay all day if you’ve paid the admission.

Q: Can I go during my period?

A: There’s no written rule against it, but Japanese custom generally discourages it. Tampon use is considered acceptable by many bathers. If you’re uncomfortable, visit another day or use a private bath.

Q: What if I have a medical condition or feel dizzy?

A: Hot water raises blood pressure. If you feel lightheaded, exit the bath immediately. Sit on the edge, cool down, drink water. People with heart conditions or high blood pressure should consult a doctor first. Most facilities have a rest area.

Q: How hot is the water?

A: Typically 40–44°C (104–111°F). Some baths go up to 46°C. Enter slowly — feet first, then lower your body gradually. The cold plunge (水風呂) is usually 15–18°C (59–64°F).

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Related Guides

• Complete Onsen Guide — Deep dive into onsen etiquette, ryokan baths, and specific hot spring regions
• Shrines & Temples Guide — Another essential cultural experience
• Payment Methods in Japan — Most sento are cash-only
• Suica Card Guide — Getting to sento by train
• Kamakura Day Trip — Combine with an Enoshima onsen visit

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