Spas with upscale

Sayulita, Nayarit

A hillside boutique hotel spa outside Sayulita with sauna, steam room, cold plunge and ocean-view pool, open on a day-pass basis.

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.

Miami, Florida

A hotel spa at Eden Roc Miami Beach in Mid-Beach with sauna, steam room, cold plunge and thermal circuits, open to resort guests only.

Taos, New Mexico

A boutique skin and body studio in Taos offering facials, lymphatic massage, Endermologie and head spa treatments by appointment.

Kamijima, Ehime

An all-inclusive resort on Yugejima island in Setouchi's inland sea, with ocean-view outdoor baths, ocean-front rooms, and a day-pass option.

San Diego, California

Hotel spa on Shelter Island in San Diego with sauna, steam room, and pool, open to guests staying at Kona Kai Resort.

Afyonkarahisar

Resort hotel in Afyonkarahisar built around thermal pools, spa treatments and physical therapy, open to hotel guests.

Spa, Liège

Hotel spa in the town of Spa, Belgium, with a thermal pool, relaxation lounge and restaurant, open to day-pass visitors, not just hotel guests.

Catskills, New York

A Catskills retreat center with a Tibetan-style spa offering sauna, steam, pools and cold plunge, built around overnight stays and group programs.

Kyle, Texas

A 88-acre Hill Country resort near Kyle and Wimberley with overnight rooms, a garden spa, pool, hot tubs and day-pass access by reservation.

San Diego, California

A hotel spa on Mission Bay in San Diego with sauna, steam room, cold plunge and thermal pools, open only to resort guests.

Adairsville, Georgia

A resort spa at Barnsley Resort in Adairsville, Georgia, offering massage, facials, reflexology, sauna and steam room, open to hotel guests only.

Ein Bokek, Southern District

A large hotel resort spa in Ein Bokek with two spa facilities, a thermal pool and 606 rooms overlooking the Dead Sea, open to hotel guests only.

Scottsdale, Arizona

A hotel spa at the 65-acre Fairmont Scottsdale Princess resort in North Scottsdale, open to overnight guests with sauna, steam room and pool access.

Atami, Shizuoka

A hotel spa in Atami with a thermal onsen pool, open only to overnight guests staying at Fufu Atami.

Catskills, New York

Adults-only resort spa in the Catskills with sauna, hot tub, yoga studio and overnight stays for hotel guests only.

Santa Barbara, California

A hotel spa inside Hotel Californian in Lower State, Santa Barbara, with a thermal pool and relaxation lounge, open to hotel guests only.

Huntington Beach, California

An adults-only hydrotherapy circuit with hot tub, sauna and steam room for guests staying at this beachfront Hyatt Regency resort in Huntington Beach.

Scottsdale, Arizona

A resort spa at JW Marriott Phoenix Desert Ridge with a thermal pool, relaxation lounge and on-site café, open to hotel guests and day-pass visitors.

Austin, Texas

A lakeside resort spa on Lake Travis in Lakeway, Texas, with pools, outdoor baths and treatments, open only to hotel guests.

Bad Blumau, Styria

Rogner Bad Blumau is a Hundertwasser-designed thermal resort in Styria with geothermal pools, outdoor baths and hotel-guest-only access.

Sedona, Arizona

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

Islamorada, Florida

Hotel spa at Three Waters Resort and Marina in Islamorada, Florida, with outdoor baths, a pool and ocean views, open to resort guests.