Spas with groups

San Miguel de Allende, Guanajuato

Family-friendly hot springs park near San Miguel de Allende with indoor and outdoor thermal pools, a kids' splash area, and day passes for walk-ins.

Temescal Valley, California

Adults-only hot springs resort in Temescal Valley with 19 outdoor mineral pools, red clay baths, and a cave-like grotto, open daily 9:30am-5pm.

Reykjavik, Capital Region

Eight oceanfront geothermal pools in Hvalfjörður, 45 minutes from Reykjavík, plus steam baths, a bistro and guest houses for rent.

Ischia, Campania

Family-run thermal pool park on Ischia's Maronti beach, open since 1973, with three sulfur-water pools, a sauna and direct beach access.

Shibu Onsen, Nagano

Reservation-only private hot spring and sauna suites at a Nagano brewery complex, built around a craft beer bathing plan for two to four guests.

Calistoga, California

A 1952 Calistoga hot springs resort with three mineral pools at 85, 95 and 104°F, mud baths, overnight rooms and a day-pass option.

Húsavík, Northeastern Region

Geothermal seawater baths built into the cliffs above Skjálfandi bay in Húsavík, with walk-in day passes and views toward the Arctic horizon.

Asan, South Chungcheong

Hot springs resort spa in Asan with thermal pools, sauna and a relaxation lounge, open daily on a walk-in day-pass basis.

Palm Springs, California

A 10-room mineral hot springs hotel in Desert Hot Springs near Palm Springs, offering day passes to its 120°F spring-fed pools, sauna and massage rooms.