World’s Largest Cruise Ship Has People Cringing: The largest cruise ship of all time, the Icon of the Seas The Royal Caribbean ship is over 250-thousand tons, there are 20 decks on the ship, seven pools, six waterslides, and room for nearly eight thousand passengers and crew. Royal Caribbean is hyping the experience onboard as “We are positioning it as the ultimate family vacation and when you step back and look at all the energy and time that has gone into creating this ship it is mind-blowing.” The first voyage in in January 2024. Check out this quick video.