Spas with family friendly

Bad Ragaz, St. Gallen

A resort thermal spa in Bad Ragaz with indoor and outdoor thermal pools and sauna, open daily 7:30am–8pm, reservation required for day passes.

Tucson, Arizona

A hotel spa at an 80-acre Sonoran Desert resort in Tucson, open to overnight guests, with three pools, hot tubs, sauna and yoga classes.

Tepoztlán, Morelos

A day spa and temazcal (traditional Mexican sweat lodge) in Tepoztlán, Morelos, open Wednesday through Sunday with reservations suggested.

Nha Trang, Khanh Hoa

A resort spa on a private peninsula near Nha Trang, open only to guests staying at the 37-villa An Lam Retreats.

Boston, Massachusetts

A hotel spa inside Mandarin Oriental, Boston's Back Bay property, open to hotel guests only, with sauna, steam room, pools and a cold plunge.

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.

San Diego, California

Hotel spa at Carté Hotel San Diego Downtown with a heated saltwater pool, whirlpool, 28,000 sq ft fitness club with sauna and steam room, open to guests only.

Oaxaca

An all-inclusive beachfront resort spa in Huatulco with a sauna, steam room and thermal pools, open only to hotel guests.

Napa Valley, California

Carneros Resort and Spa is a luxury hotel spa in Napa Valley with outdoor soaking tubs, garden lounges and treatments reserved for overnight guests.

Tulum, Quintana Roo

Resort spa at an all-inclusive Tulum beach hotel, with hydrotherapy, jungle and beach-side treatment cabins, open to hotel guests only.

Calistoga, California

MoonAcre Spa & Baths is a day spa in Calistoga with a thermal pool, hot tub and sauna, open daily 9am–5pm and geared toward families and couples.

Carmel-by-the-Sea, California

A golf-and-wellness resort spa in Carmel Valley, open to hotel guests only, with a heated pool, fitness cabanas and treatments at Spa Adeline.

Sedona, Arizona

A boutique resort spa in Sedona with a heated pool, hot tub, yoga and massage, open only to hotel guests.

Philadelphia, Pennsylvania

A private-reservation spa in Philadelphia's Manayunk neighborhood for date nights, birthday and bachelorette parties, with hot tub, sauna and massage chairs