The Onsen · 湯
The water is the whole point.
Everything else here — the sauna, the salt, the food — orbits three pools of precisely tempered, mineral-dosed water.
41°C
The Hot Bath — Kusatsu minerals
We import powdered mineral content from Kusatsu, Japan's most celebrated hot-spring town, and dose the hot bath daily — sulfur-rich water softened with citrus essential oil. Ten minutes at 41 °C and the day loosens its grip: shoulders drop, breath slows, the head goes quiet. This is the bath the Japanese guests write home about.
38°C
The Warm Bath — the long soak
A degree above body temperature, dosed with Epsom salts. This is the social pool — the one you stay in for an hour under the projection wall while the conversation drifts. Nowhere to be, nothing to prove, no reason to leave.
19°C
The Cold Plunge — the reset
Nineteen degrees of pure clarity. Thirty seconds after the hot bath and every nerve ending reports for duty. Alternate hot and cold three rounds — the classic Japanese sequence — and finish cold. You'll sleep like a stone tonight.
The ritual
Hot → cold → rest. Repeat ×3.
Wash first at the shower stations — always. Then: ten minutes hot, one minute cold, ten minutes horizontal in the rest lounge. Do the circuit three times and end with the Japanese set meal that comes with your entry. That's the Maxwell afternoon. New to onsen? Read the first-timer's guide — two minutes and you'll walk in like a regular.
In the water
Bath etiquette, briefly.
- · Shower thoroughly at the wash stations before any bath.
- · The baths are enjoyed nude, as in any true Japanese onsen — towels are for walking between rooms.
- · No soap, drinks or food in the pools. Tie up long hair.
- · Rinse between the sauna and the water.
- · Tattoos are completely welcome — this is Bangkok, not Kusatsu.
Onsen or sauna?
Both. In that order.
An onsen is a Japanese bathing tradition built around mineral-rich hot pools; a sauna is dry or steam heat in a room. Maxwell is the first, with the second inside it — a pine dry sauna, a bergamot-and-lemongrass steam room and a Himalayan salt room, all on the same ticket.
Want to see the bath hall before you're standing in it? Phones stay in the lockers here, so the 360° virtual tour is the way to look around in advance — granite pools, waterfall spouts and the projection wall, in every direction.
No booking. Just come.
The water is already warm.
173/3 Surawong Road, Silom · Entry ฿600 with a full Japanese meal included · Mon–Fri 2 PM–midnight, Sat–Sun 12 PM–midnight.