Spas with upscale

Wulai, New Taipei

A hilltop Wulai B&B with sodium bicarbonate hot-spring baths in every room and an outdoor infinity pool, geared toward couples.

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.

Hunter Valley, New South Wales

A resort spa inside Avani Cypress Lakes in Pokolbin, open to hotel guests for treatments, thermal pools, outdoor baths and a fitness and yoga space.

Naples, Florida

A boutique hotel in downtown Naples with a heated outdoor pool, whirlpool spa and cabanas, open only to overnight guests.

Boston, Massachusetts

Hotel spa inside the Omni Boston Hotel at the Seaport, with eight treatment rooms and a rooftop pool, open to hotel guests only.

Calistoga, California

A 1952 Calistoga hot springs resort with three mineral pools at 85, 95 and 104°F, mud baths, overnight rooms and a day-pass option.

Scottsdale, Arizona

Hotel spa at the mid-century Hotel Valley Ho in South Scottsdale, with sauna, steam room and two pools, open to hotel guests only.

Chicago, Illinois

Upscale day spa in Lincoln Park, Chicago, where booking any treatment unlocks all-day access to a hydrotherapy circuit, thermal suite and outdoor terrace.

The Hamptons, New York

A medical day spa in East Hampton offering 22 botanical-based facials, massages and oncology-support treatments, open daily 10am–6pm.

Hilton Head Island, South Carolina

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

Seattle, Washington

A med spa and beauty bar inside Seattle's Fairmont Olympic Hotel, open daily with facials, injectables, massage and nail services by appointment.

Jackson Hole, Wyoming

Hotel spa at Snake River Lodge in Teton Village with a pool and hot tub, open daily 10am–5pm, restricted to hotel guests.

Washington, D.C., District of Columbia

Hotel spa at Pendry Washington DC - The Wharf with eucalyptus steam rooms, a heated whirlpool and an outdoor terrace pool, open daily 10am-6pm.

Philadelphia, Pennsylvania

Hotel spa on the third floor of The Rittenhouse overlooking Rittenhouse Square, with massage, facials, body treatments and a salon.

Sonoma, California

Hotel spa at The Lodge at Sonoma with an outdoor terrace, soaking pool, plunge pool and barrel sauna, open daily 9am-5pm, adults-only, reservation required.

Kuala Lumpur

Hotel spa on the 6th floor of The RUMA in Kuala Lumpur, open daily 10am-9pm, restricted to hotel guests.

Hudson Valley, New York

Hotel spa inside The Abbey Inn in Peekskill, overlooking the Hudson River, with six treatments including a Japanese head-and-foot package.

Ojo Caliente, New Mexico

Historic New Mexico hot springs resort with communal mineral pools, private tubs, and day-pass soaking near Taos.

Sedona, Arizona

A resort spa at Amara in Sedona with outdoor baths, an infinity pool and a relaxation lounge, open only to hotel guests.

Rishikesh, Uttarakhand

An upscale riverside resort 18 km outside Rishikesh with an in-house spa, yoga studio and restaurant, open only to overnight guests by reservation.

Mérida, Yucatán

Resort spa on the grounds of Hacienda Xcanatun near Mérida, with a pavilion over a pond offering Asian-style massages and facials by reservation.

Tucson, Arizona

A hotel spa inside the 1929 Hacienda del Sol Guest Ranch Resort in Tucson, offering facials, massages and body treatments to resort guests only.

Tucson, Arizona

Lakeside Spa at this 398-room desert resort in Tucson is open to hotel guests only, with two heated pools, a Jacuzzi and mountain views of Catalina range.

Dallas, Texas

Mokara Spa is the full-service hotel spa inside Omni Dallas Hotel in the Downtown Historic District, open to hotel guests.