The first trip will be a seven-day voyage around islands in the Caribbean, but there are concerns about methane emissions from the ship.
Environmentalists have warned that the liquefied natural gas (LNG) used to power the ship could leak harmful methane into the air.
What do we know about the cruise ship “Icon of the Seas”?
The 365-meter (1,197-foot) ship, owned by Royal Caribbean Group, is five times larger than the Titanic.
Weighing over 250,000 tons, it has 20 decks and can accommodate up to 7,600 passengers.
But tickets aren’t cheap! It costs between $1,723 (£1,360) and $2,639 (£2,083) per person to take a cruise. This time we will stop in St. Kitts and Nevis and Charlotte Amalie in the US Virgin Islands.
The giant ship was built at a shipyard in Turku, Finland, but is registered in the Bahamas Islands in the Caribbean.
The cruise ship has seven swimming pools, six water slides, an onboard water park called Thrill Island, and an amusement park on the top deck.
The ship cost $2 billion (£1.6 billion) to build and has more than 40 restaurants, bars and lounges on board.
Last week, Argentina’s World Cup-winning captain Lionel Messi attended the ship’s naming ceremony.
He put his own football-themed spin on the traditional “good luck” symbol of smashing a champagne bottle against the bow by placing the ball on a special stand.
Why are people concerned about the environmental impact of ocean icons?
The ship is powered by liquefied natural gas (LNG), which generates less carbon dioxide, a greenhouse gas that causes global warming, than regular ships that use heavy oil.
However, there is a risk that some of the gas could leak and methane could leak into the atmosphere.
Atmospheric methane traps 80 times more heat than carbon dioxide over 20 years, and reducing these emissions is considered important to slowing global warming.
The International Council on Clean Transport (ICCT) recently released a report claiming that methane emissions from LNG-fueled ships are higher than expected under current regulations.
“This is a step in the wrong direction,” said Brian Comer, marine program director.
“Using LNG as a marine fuel is estimated to increase lifecycle greenhouse gas emissions by over 120% compared to marine diesel oil.”
Royal Caribbean says Icon of the Seas is 24% more energy efficient than the International Maritime Organization requires for modern vessels.
The company also plans to introduce net-zero ships by 2035.