Ships So Big They Need Their Own Zip Code: 2027's Giants

Royal Caribbean’s Icon class holds the "world’s biggest cruise ship" title outright, and each new sister ship has nudged the record slightly further. The headline feature across the class is the Infinite Balcony — a floor-to-ceiling window in every stateroom that opens like a balcony without a traditional overhang — alongside eight themed "neighbourhoods" and the largest waterpark at sea.

At 175,500 gross tonnes and carrying around 4,300 guests, Sun Princess is the largest ship Princess Cruises has ever built — and the first in its new Sphere Class. Its signature feature is The Dome, a striking geodesic glass structure inspired by the terraces of Santorini that functions as a pool deck by day and a nightlife venue after dark. Sun Princess also carries more balcony cabins than any previous Princess ship, giving more guests a private view as standard.

Due to debut in May 2027 with a transatlantic sailing from Southampton to Port Canaveral, Carnival's Carnival Festivale will be the line’s largest ship yet. Its headline act is Sunsation Point, a three-deck family zone built around Carnival’s biggest-ever WaterWorks water park, with six slides, a splash pad for younger kids, and an elevated ropes trail. Once settled into Florida service, Festivale will run 6–8 night Caribbean itineraries from Port Canaveral alongside sister ship Mardi Gras.

Not long ago, Royal Caribbean’s Oasis-class ships — led by Symphony of the Seas at 228,081 gross tonnes, with 18 decks and seven onboard "neighbourhoods" — held the world’s-biggest title for the best part of a decade. Symphony’s highlights, like its 10-storey slide and the Ultimate Abyss, set the template that Icon-class ships have since built on and outgrown. If megaships are your thing, Symphony and her Oasis-class sisters (Harmony, Allure and Oasis of the Seas) are all still sailing and remain some of the biggest ships afloat — just no longer the biggest.

Yes — Flight Centre can book all of these ships, though most sail from US, European or Caribbean home ports rather than Australia, so you’ll usually combine the cruise with international flights. Ask your Cruise Expert about fly-cruise packages and current RCI, Princess and Carnival offers.