Spas with private suites

Puyehue, Los Lagos

A hot-springs resort inside Puyehue National Park with two mineral pools, cabins, river-side domes, camping, and day passes for non-guests.

Miami, Florida

A 12,000-square-foot hotel spa at Coral Gables' Biltmore, with eucalyptus steam rooms, Himalayan salt saunas and a couples suite; adults-only, reservation

Lake Tahoe, California

A 17-room, adults-only hotel spa at Lake Tahoe's Ritz-Carlton with a heated lap pool, sauna and steam room; day pass access requires booking a treatment.

Los Angeles, California

Downtown LA hotel spa at the Ritz-Carlton with massages, facials, a couples suite, rooftop pool and gym; outside guests need to book a treatment to enter.

Calistoga, California

Hotel spa in downtown Healdsburg with a garden patio, jacuzzi and pool access, open daily 9am-5pm for guests and day visitors.

Palm Springs, California

A 38,000-square-foot resort spa at JW Marriott Desert Springs in Palm Desert offers day passes, saunas, a saltwater lap pool and couples suites.

Denver, Colorado

A hotel spa in downtown Denver with a $150 day pass covering pool, steam room, whirlpool and fitness centre access, open to non-guests.

Houston, Texas

A Four Seasons hotel spa in downtown Houston with three treatment rooms, a couples' suite and rooftop pool access, open to day-pass guests.

Milan, Lombardy

A luxury hotel spa inside Four Seasons Hotel Milano with a 14-metre pool under a vaulted ceiling, sauna, gym and private suites for couples' treatments.

Nashville, Tennessee

A hotel spa in downtown Nashville with six treatment rooms, a rooftop infinity pool, and day passes open to non-guests.

Bora Bora

A hotel spa at Four Seasons Resort Bora Bora with glass-floor treatment suites over the lagoon, limited to resort guests.

Jackson Hole, Wyoming

A hotel spa at Four Seasons Jackson Hole with treatment suites, whirlpools, a cold tub, salon services and fitness facilities, reservation-only.

Santa Fe, New Mexico

A hotel-guests-only resort spa in Santa Fe with 15 treatment rooms, private soaking courtyards, saunas and steam rooms, built around Southwest-inspired rituals.

Tucson, Arizona

Six-room hotel spa at Hacienda del Sol in Tucson, open daily 9-6, taking both resort guests and local walk-ins for massages, facials and body treatments.

Boston, Massachusetts

Hotel spa inside the Four Seasons One Dalton in Back Bay, with six treatments, a couples' suite and a 64-foot lap pool, open to hotel guests.

Scottsdale, Arizona

Adults-only hotel spa at the Fairmont Scottsdale Princess with a rooftop pool, grotto waterfall pool, sauna, steam room and cold plunge, open daily 6am-7pm.

The Colony, Texas

A day-soaking spa in The Colony with mineral pools at varying temperatures, seven saunas, cold plunges and a poolside café.

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.

Coorg, Karnataka

Riverside resort spa in Coorg with private bungalows, a pool, and spa treatments along the Kaveri River; booking required.

Soufrière

Resort spa at Ladera in Soufrière, St Lucia, set between the Pitons with day-pass access to pools, outdoor baths and treatments for couples.

Asheville, North Carolina

Ayurvedic destination retreat in the Blue Ridge Mountains near Asheville, with day-pass spa visits and multi-night panchakarma cleanses by reservation.

Coorg, Karnataka

A luxury coffee-plantation resort in Coorg with a spa and pool facilities reserved for overnight guests.

Seville, Andalusia

A reservation-only private spa suite with pool in Seville's Casco Antiguo, booked by the hour for couples.

Beitou, Taipei

A hot-spring resort in Beitou, Taipei with private suites, outdoor baths and overnight stays, open to day-pass visitors by reservation.