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.

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.

Fort Lauderdale, Florida

Mokara Spa inside the Omni Fort Lauderdale Hotel has the area's only hammam, plus treatment rooms, a pool deck and rooftop bar, open to hotel guests only.

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.

The Hamptons, New York

A 29-room boutique hotel in Southampton with a poolside bathing club, relaxation lounge and restaurant, 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.

Sint Eustatius

A 40-acre dive-and-stay resort on Sint Eustatius with a pool, restaurant and shuttle service to its dive center, open only to overnight guests.

Napa Valley, California

Spa Terra is the cave-set spa at Meritage Resort in Napa Valley, open to hotel guests with pools, a relaxation lounge and on-site dining nearby.

Scarborough

A boutique hillside hotel above Bacolet Bay in Scarborough, Tobago, with an infinity pool and ocean views, built around a converted 150-year-old Donkey Cart

Catskills, New York

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

Naples, Florida

A resort spa at the Hyatt Regency Coconut Point in Bonita Springs, open to hotel guests by reservation, with pool access on site.

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.

Austin, Texas

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

Ojai, California

Hotel spa at the Ojai Valley Inn resort, open only to overnight guests, with pool and restaurant access on site.

Palm Springs, California

A hotel spa at Palm Springs' Riviera Resort & Spa, open only to overnight guests and paired with a pool, restaurant and bar.

Puerto Vallarta, Jalisco

An all-inclusive family resort on Puerto Vallarta's hotel-zone beach, with a spa (opening soon) offering massages, facials and other treatments for guests only.