MS Harmony of the Seas is an Oasis Class Cruise Ship built by STX France at the Chantiers de l'Atlantique shipyard in Saint-Nazaire, France for Royal Caribbean International. With a gross tonnage of 226,963 GT, she was the LARGEST PASSENGER SHIP IN THE WORLD, surpassing her older sisters Oasis of the Seas and Allure of the Seas.  However, with the 2018 debut of the Symphony of the Seas, that torch was passed.

Harmony of the Seas has 2,747 staterooms, with a wide variety of types, to accommodate (at double occupancy) 5,479 guests ranging from small interior rooms through larger rooms to suites, some of which are fitted with wall-mounted 80-inch (200 cm) screens, covering nearly the floor to ceiling, that show the ship's environment as if through a window, named 'virtual balconies'. These screens were first fitted on the Quantum Class of cruise ships.  A full 43 categories of stateroom types are offered, starting at a size of 180 square feet (17 m2); several types of suites are available, including the new "Royal Class" suites.

As the third member of the Oasis class, Harmony of the Seas is very similar to her two sister ships. However, there are some design changes and extra amenities, most noticeably the "Ultimate Abyss" dry slide at the stern of the ship and the "Perfect Storm" water slides.  Harmony of the Seas is the second Royal Caribbean ship to feature water slides, after Liberty of the Seas underwent a refurbishment in January 2016 that added water slides and Splashaway Bay. The ship is divided into seven neighborhoods, including Central Park and Boardwalk, like her Oasis-class sisters.  Amenities include: 

  • "Vitality" Spa and fitness center
  • "Splashaway Bay" water play area for young children
  • "Perfect Storm"  water slide complex, featuring three slides
  • "Ultimate Abyss" dry slide complex, with two ten-story tall enclosed slides
  • 4 swimming pools and 10 hot tubs, including two hot tubs cantilevered over the edge of the ship
  • 2 Flowrider surf simulators
  • "Casino Royale"  casino with a full selection of slot machines and table games
  • "Puzzle Break: Escape the Rubicon"  escape room game designed by Seattle-based Puzzle Break and ShowFX
  • 20 dining venues,  including "Wonderland" molecular gastronomy restaurant
  • 11,252 works of art
  • Studio B Ice Rink
  • The Aqua Theatre, an open-air stage which hosts diving, aerial and acrobatics shows
  • The Bionic Bar, where drinks are made solely by two robotic arms
  • The Royal Theatre, a 1,400 seat venue for Broadway-style shows such as Grease, Royal Caribbean's original show Columbus, and 3D movies
  • DreamWorks Experience, with characters from Shrek, Kung Fu Panda, etc.
  • Two rock climbing walls
  • Full-size basketball court, miniature golf course and ping pong tables
  • Zipline
  • Adventure Ocean programs for children and youth; also Royal Babies and Royal Tots programs
  • "Voom" high-speed Internet
  • Optional RFID enabled wristbands (WOWbands) which will provide the same functions as the SeaPass cards
  • Promenade shopping mall featuring jewelry, fashion and accessories
  • Rising Tides Bar, a bar platform that raises and lowers three floors between the Promenade level and the Central Park level
  • Carousel, Johnny Rockets, Starbucks, snacks and entertainment on the Boardwalk area
  • Central Park, an open air garden path with food and shops