Spas with upscale

Palm Springs, California

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

Plainfield, Indiana

Day spa in Plainfield, IN offering facials, massages and body-sculpting treatments alongside a sauna, steam room and thermal pool, reservation required.

Miami, Florida

A beachfront resort spa in North Beach, Miami with cryotherapy, a floating salt bath, sauna, steam and a cold plunge, open to walk-ins and day-pass guests.

Bridgetown, Christ Church

Hotel spa at Accra Beach Hotel in Christ Church, Barbados, with six treatment rooms, a sauna and steam room, open daily 8am-7pm for hotel guests.

San Diego, California

A La Jolla medical spa specializing in lymphatic drainage, colon hydrotherapy and detox treatments, open since 1993, adults only, by reservation.

Hilton Head Island, South Carolina

Hotel spa inside an oceanfront Hilton Head resort, offering massages, facials, body treatments and manicures to overnight guests.

San Diego, California

A resort spa on a 44-acre Mission Bay island in San Diego, open to hotel guests, with sauna, steam room and pool access.

Riviera Maya, Quintana Roo

Beachfront all-inclusive resort in Playa del Carmen with a hydrothermal circuit spa available to hotel guests for an extra charge.

Riviera Maya, Quintana Roo

A resort spa inside the Iberostar Waves Tucán in Playacar offering sauna, Turkish bath and jet-pool treatments, open to day-pass visitors 16 and up.

Jekyll Island, Georgia

Hotel spa at Jekyll Island Club Resort offers outdoor baths and a pool with ocean views, open only to resort guests.

San Juan

Adults-only hotel spa inside La Concha Resort in Condado, San Juan, offering couples massages and a small treatment menu for guests 18 and up.

Riviera Maya, Quintana Roo

A resort spa inside the all-inclusive Iberostar Waves Cozumel beach hotel, open to day-pass visitors as well as overnight guests.

Tucson, Arizona

Adults-only day spa in Tucson's Triangle area offering lymphatic facials, dermaplaning and a hydrotherapy circuit; reservations required.

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.

Cancún, Quintana Roo

The spa at this all-inclusive Puerto Morelos resort offers hydrotherapy, massages and facials for hotel guests only.

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.

Punta Cana, La Altagracia

A hotel spa inside the adults-only JOIA Bávaro by Iberostar beach resort in Punta Cana, open only to overnight guests.

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.

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.

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.

Fort Lauderdale, Florida

A hotel spa at the Fort Lauderdale Marriott Harbor Beach Resort, open to hotel guests, with ocean views, a relaxation lounge and an on-site restaurant.

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