Spas with upscale

Chicago, Illinois

Thermal baths and spa rituals in a restored 1902 factory in West Town, Chicago, open daily for adults-only soaking and massage packages.

Austin, Texas

Hotel spa inside W Austin with seven treatment rooms, 22 services including couples massage, and access to the rooftop WET pool deck.

Bagno Vignoni, Tuscany

Hotel spa in a 15th-century Bagno Vignoni palazzo with a thermal pool fed by the village's natural hot springs, open to day visitors.

Aspen, Colorado

A reservation-only Aspen studio offering private sound, energy and subconscious-journey sessions instead of classic spa treatments.

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.

Tenerife, Canary Islands

A hotel spa at Bahía del Duque in Costa Adeje with an outdoor seawater thalassotherapy circuit, hammam, saunas and a cold plunge, open to day visitors.

Orlando, Florida

A six-treatment-room hotel spa at Wyndham Grand Orlando with 54 services, a hot tub and relaxation lounge, open daily 10am–6pm.

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.

Florence, Tuscany

A 650-square-meter spa inside a 14th-century Florence monastery, with thermal pool, guesthouse rooms, bistro and day-pass access.

Tabernash, Colorado

A resort spa at Devil's Thumb Ranch in Tabernash, Colorado, open only to overnight guests, with a geothermal pool, hot tub and couples treatments.

Jackson Hole, Wyoming

A day spa next to the Trailborn hotel in Jackson Hole with an outdoor pool deck, salt lounge and day passes for walk-in soaks or treatments.

Houston, Texas

Day spa in Houston's Westside with a grotto pool, outdoor pool, steam rooms and sundeck, plus an on-site restaurant; walk-ins welcome.

The Hamptons, New York

Oceanfront resort spa in Montauk with a seawater and marine-based treatment menu, hydrotherapy, contrast bathing, and a heated saltwater pool.

Gold Coast, Queensland

An overnight wellness retreat in Tallebudgera Valley with a cedar sauna, magnesium spa bath, ice bath and a 60-minute aromatherapy massage.

Opatija, Primorje-Gorski Kotar

A 5-star hotel spa in Opatija with a sauna centre, seawater pools and couples treatments, open only to Hotel Ambasador guests.

Portorož, Coastal-Karst

Hotel spa on Portorož's seafront promenade with heated seawater and thermomineral pools, open to day visitors as well as hotel guests.

Valle de Bravo, State of Mexico

A forest hotel spa outside Valle de Bravo built around a hydrotherapy circuit of hammam, sauna, cold pool and contrast pools, open to overnight guests only.

Velingrad, Pazardzhik

Hotel spa in Velingrad with mineral-water pools, saunas, steam rooms and a hammam spread over 4,000 square metres; day passes are available.

Archena, Murcia

A 19th-century thermal hotel in Archena with direct access to a Roman-era spring complex, open to day visitors as well as overnight guests.

Houston, Texas

Upscale day spa at The Houstonian in Houston with 22 treatment rooms, soaking pools and a sundeck; pool access comes with a 50-minute-plus treatment, not a

Tucson, Arizona

Hotel spa at the Westin La Paloma Resort in Tucson offering massages, facials and body treatments, open only to resort guests.

Scottsdale, Arizona

Adults-only hotel spa at The Scott in Scottsdale with six treatment rooms, sauna, steam and pools, plus day passes for non-guests.

Tucson, Arizona

Hotel spa at Loews Ventana Canyon Resort, Tucson, with eight treatment rooms, an adults-only pool, and a 24-hour fitness center; open daily 9am–6pm.

Chicago, Illinois

Hotel spa on the lower level of the Fairmont Chicago, open to guests for massages, facials and a couples suite with an infinity-edge soaking tub.