Spas with family friendly

New York City, New York

A Flatiron bathhouse with six thermal pools, a banya, dry and infrared saunas, a steam room and a salt pool, day pass from $39.

Dogo Onsen, Ehime

A roughly 3,000-year-old public hot spring bathhouse in Matsuyama, designated an Important Cultural Property, open daily with walk-in day passes from 700 yen.

Oslo

Waterfront sauna spot on Aker Brygge with shared and private saunas, sea bathing, and sauna boat trips on the fjord.

Arima Onsen, Hyogo

A moderately priced onsen bathhouse in Arima Onsen, Kobe, with a forest sauna, a large outdoor bath, yoga and an award-recognized restaurant.

Ibusuki, Kagoshima

Oceanfront outdoor onsen in Ibusuki where the two gender-assigned baths swap daily, with views of Mount Kaimon, the East China Sea, and Take-yama.

Ho Chi Minh City

A Korean-style jjim jil bang in Ho Chi Minh City with six heated rooms, a Dead Sea mineral soaking pool, and massage, hair-wash and facial services.

Gold Coast, Queensland

A 90-minute hydrotherapy circuit in Southport with a Finnish rock sauna, 5° ice baths and hot/cold magnesium pools, day pass $49.

New York City, New York

A Brooklyn bathhouse built around the largest banya in the US, with Turkish and Moroccan hammams, multiple saunas and a hydrotherapy pool circuit.

Noboribetsu, Hokkaido

A plain neighborhood bathhouse in Noboribetsu, Hokkaido, offering 100% source-fed hot spring water in two mineral varieties, about 10 minutes from the station.

Cotswolds, England

A wood-fired riverside sauna at Whichford Mill in the Cotswolds, with a cold-plunge bath, river dipping, and both private and communal sessions.

Ginzan Onsen, Yamagata

A no-frills communal bathhouse in Ginzan Onsen's Taisho-era hot spring street, open daily 8:30am-3:30pm except Wednesdays.

Arima Onsen, Hyogo

Hotel spa in Arima Onsen with Arima's rare iron-rich "ginsen" waters, outdoor baths, sauna and jacuzzi, run as an all-inclusive overnight stay.