Spas with upscale

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.

Sonoma, California

A Sonoma medical day spa run by a 25-year skincare specialist, offering non-toxic facials, microcurrent and micro-channeling treatments up to $350.

Minneapolis, Minnesota

Hotel spa inside Hotel Ivy in downtown Minneapolis, offering massages, facials, body treatments and a steam room on the hotel's second floor.

Aspen, Colorado

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

Dallas, Texas

A Dallas day spa near University Park offering massage and facial treatments, with a $220 signature 60-minute ritual and walk-in availability.

Bangkok

Hotel day spa in Sathon with four signature treatments, couples rooms, and daily walk-in access from 10am to 8pm.

Washington, D.C., District of Columbia

A Northwest DC day spa on 14th Street specializing in massage, facial and skincare treatments, with walk-ins accepted but reservations recommended.

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.

Prague

A day spa near Wenceslas Square in Nové Město offering massages, facials and thermal pool access with day passes for walk-ins.

Istanbul

A working Ottoman hammam built in 1741 in Istanbul's Fatih district, offering traditional bath rituals with no day-pass option, only full treatments.

Miami, Florida

Hotel spa inside Dua Miami, Autograph Collection in Brickell, open daily 9am-6pm, with sauna, steam room, cold plunge and couples massage rooms.

Chicago, Illinois

Facial-focused day spa in Lakeview run by two master estheticians, offering customized skincare and body treatments by appointment near the Belmont L stop.

Florence, Tuscany

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

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.

New York City, New York

A below-street-level day spa in NoHo with thermal baths, a three-story indoor waterfall, sauna, steam room and cold plunge, plus massage and facial treatments.

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.

Doha

Hotel spa at The Westin Doha with some of the city's largest wet facilities, accessible to hotel guests and members only, no day passes sold.

Philadelphia, Pennsylvania

Herb & Gem Spa is a small day spa in South Philadelphia offering massage, facial and reflexology packages with walk-in day passes.

Los Angeles, California

A Brentwood day spa on Wilshire Blvd focused on facial treatments, with a signature facial priced at $220 and couples treatments available.

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.

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.

Miami, Florida

A Peruvian-themed day spa inside the Victor Hotel on Ocean Drive, South Beach, with a hamam, steam room, sauna and a couples suite.