Spas with upscale

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.

The Hamptons, New York

A 29-room boutique hotel in Southampton with a poolside bathing club, relaxation lounge and restaurant, open to hotel guests only.

Scottsdale, Arizona

A hotel spa at the 65-acre Fairmont Scottsdale Princess resort in North Scottsdale, open to overnight guests with sauna, steam room and pool access.

Sint Eustatius

A 40-acre dive-and-stay resort on Sint Eustatius with a pool, restaurant and shuttle service to its dive center, open only to overnight guests.

Napa Valley, California

Spa Terra is the cave-set spa at Meritage Resort in Napa Valley, open to hotel guests with pools, a relaxation lounge and on-site dining nearby.

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

Naples, Florida

A resort spa at the Hyatt Regency Coconut Point in Bonita Springs, open to hotel guests by reservation, with pool access on site.

Austin, Texas

A lakeside resort spa on Lake Travis in Lakeway, Texas, with pools, outdoor baths and treatments, open only to hotel guests.

Palm Springs, California

A hotel spa at Palm Springs' Riviera Resort & Spa, open only to overnight guests and paired with a pool, restaurant and bar.

Puerto Vallarta, Jalisco

An all-inclusive family resort on Puerto Vallarta's hotel-zone beach, with a spa (opening soon) offering massages, facials and other treatments for guests only.

Sedona, Arizona

A boutique resort spa in Sedona with a heated pool, hot tub, yoga and massage, open only to hotel guests.

Islamorada, Florida

Hotel spa at Three Waters Resort and Marina in Islamorada, Florida, with outdoor baths, a pool and ocean views, open to resort guests.