Deep Ocean Spa, at the InterContinental Bora Bora Resort & Thalasso Spa, features overwater treatment rooms with glass-paneled floors, so you can spy on fish during a full-body rub-down. Afterward, enjoy the al fresco hydrotherapy circuit, which utilizes mineral-rich sea water pumped from 3,000 feet below the Pacific. Treatments start from $108.

The Fontainebleau’s a 40,000-square-foot Lapis Spa is centered around thermal therapies and relaxing water treatments. Indulge in mineral water jet baths, rain tunnels, and the Bleau Rain Room, which envelops guests in a blue haze as warm water-jets massage the body. Treatments start at $90, day packages from $166.

You’ll want to arrive an hour before your appointment at the Waldorf Astoria’s water-centric Spa Grande: Guests who book a spa treatment can soak in the soothing waters of its hydrotherapy circuit, which includes five aromatic baths, a bubbling Japanese Furo, a Roman hot tub, a cold plunge, and three 10-foot waterfalls designed to massage your neck and shoulders. Treatments start from $65.

Huvafen Fushi’s Lime Spa boasts world’s first underwater treatment rooms, with huge windows peering out to coral reef, schools of fish, and the ocean floor. There are also a variety of hot- and cold-water therapies to enjoy pre-treatment. Underwater full-body treatments start at $285 for a 60-minute massage.

Twenty minutes south of Cancun, the oceanfront Zoëtry Paraiso de la Bonita resort features a 22,000-square-foot thalasso center and spa focused on therapies using warm seawater, seaweed, and marine mud. Treatments start at $90 for 20 minutes in the thalasso bathtub with a jet massage; add on a head massage or a glass of drinkable micro-filtrated ocean seawater for $9.

During days at sea when you are surrounded by water, you can soak up its benefits in the Mandara Spa onboard the new Norwegian Bliss. There is a salt room, a snow room, a trio of pools, thermal benches, and saunas all aimed at detoxifying and healing; as well as large windows, where you can watch the ocean waves as you relax before or after a treatment. Treatments start from $99.

Just yards from Atlantic Ocean, Qua Baths & Spa features impressive Roman Baths—three pools of varying temperatures—as well as an herbal steam room, both of which are included as a prelude to every treatment. Treatments start from $90, and every Friday, you can get 20-percent-off of any 75-minute spa service.