Spas with groups

Napa Valley, California

Adults-only resort spa built into a wine cave in Napa, with a vineyard-view pool, sauna, steam room and hot tub; reservations required.

Austin, Texas

Hotel spa at Hotel Viata in West Lake Hills with treatment rooms, a couples suite, pool, sauna, steam room and a day-pass option for amenity access.

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.

London, England

A Russian-style banya bathhouse in Belgravia offering oak-lined steam rooms, cold plunge pools and leaf-massage rituals, with day passes by reservation only.

Wanaka, Otago

A lakefront wood-fired sauna at The Outlet in Wānaka running guided or self-guided group sessions with cold dips in the lake between rounds.

Los Angeles, California

Four Seasons hotel spa in Beverly Hills with a steam room, rooftop pool, fitness center and eight treatments, open daily, day passes available.

Chicago, Illinois

A 5th-floor day spa inside the Palmer House Hilton in the Loop, built around a hydrotherapy circuit, Vichy shower treatments and a facial called Glow Revival.

Philadelphia, Pennsylvania

Hotel spa in Center City Philadelphia with a heated indoor saltwater pool, fitness center and day-pass access for non-guests.

Portland, Oregon

A 21-and-up day spa in Portland's Irvington neighborhood built around vinotherapy, with wine-infused baths, massages and Caudalie facials.

Philadelphia, Pennsylvania

A Roxborough day spa with a Vichy shower and glass-walled hammam, built for massages, facials, nail care and group spa parties.

Austin, Texas

Hotel spa inside Austin Proper with 15 treatments, a cold plunge and sauna recovery room, open daily by reservation.

Los Angeles, California

Day spa in West Hollywood with wet and dry banyas, pool, sauna, cold plunge and café; day pass is $110, walk-ins welcome.

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.

Tallinn, Harju County

A small hotel spa in central Tallinn with three treatment rooms, two saunas and a Japanese pool, offering massages and facials by appointment.

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.

Thatcher, Idaho

A riverside hot springs in Thatcher, Idaho, with outdoor thermal pools, day passes, and overnight stays in yurts, cabins, or tents.

Olmué, Valparaíso

A boutique lodge and spa in the Olmué valley, about 80 minutes from Santiago, with a thermal pool, outdoor baths and day passes for non-guests.

Dublin, Leinster

An outdoor barrel sauna and cold plunge pool setup in Saggart, Dublin, booked in 50-minute sessions for groups and couples.

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.

Sedona, Arizona

A resort spa at Amara in Sedona with outdoor baths, an infinity pool and a relaxation lounge, open only to hotel guests.

Rishikesh, Uttarakhand

An upscale riverside resort 18 km outside Rishikesh with an in-house spa, yoga studio and restaurant, open only to overnight guests by reservation.

Leukerbad, Valais

A 30-room hotel in Leukerbad with a private thermal pool and sauna chalet, open to overnight guests only, overlooking the Gemmi massif.

Transylvania County, North Carolina

All-inclusive multi-night wellness retreat in Pisgah Forest, NC, combining fitness classes, spa treatments, guided hikes and farm-to-table meals in private