Royal Caribbean has spent two decades building ever larger cruise ships, and the biggest now dwarf anything that sailed a generation ago. The line’s Oasis and Icon classes include vessels weighing well beyond 225,000 tons, each carrying more than five thousand guests. Here are eight of them, ranked from the largest down to the smallest, with debut years and key figures.
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1. Icon of the Seas: Pioneer Of A New Class
Royal Caribbean’s own guide to the line’s Icon class cruise ships describes each vessel as massive, measuring 1,196 feet long across 20 decks. At 248,663 tons, Icon of the Seas sits at the top of the fleet’s size ranking and gives the class its name. The ship is built around a vacation-resort concept, with the largest waterpark at sea as one of its signature attractions.
Icon of the Seas debuted in 2024 and carries about 5,610 guests at double occupancy. A ship of this scale works almost like a floating town, with neighborhoods, dining venues, entertainment spaces and pools spread across its many decks. For travelers comparing megaships, it serves as the benchmark against which every other Royal Caribbean vessel is now measured.
2. Star of the Seas: The Icon Sequel
Royal Caribbean’s ships by age table lists Star of the Seas as an Icon-class vessel that entered the fleet in 2025. Its gross tonnage of 248,663 matches the first ship of the class exactly, which is why the two share the top spot among the line’s vessels. Guest capacity is listed at 5,610 at double occupancy.
As the second Icon ship, Star of the Seas follows the same basic design as its older sibling, a pattern common when cruise lines build sister ships in a series. Passengers booking either vessel can expect a comparable scale of onboard space and amenities.
3. Utopia of the Seas: A Slightly Smaller Giant
Utopia of the Seas joined the fleet in 2024 as part of the Oasis class, and its 236,473 tons make it a true megaship by any standard. The Oasis-class article on Wikipedia’s class overview notes that Utopia is the first in its class not to be the world’s largest cruise ship.
That distinction reflects timing rather than any shortfall. Earlier Oasis vessels each arrived as the biggest passenger ship afloat, but by the time Utopia appeared, the larger Icon design was already setting a new ceiling. Even so, the ship remains one of the biggest cruise vessels ever built and sits well above the 225,000-ton mark that defines this list.
4. Wonder of the Seas: Once The World’s Largest
Wonder of the Seas entered service in March 2022 as the largest ship in the world, according to Royal Caribbean’s fleet age listing. The Oasis-class vessel weighs 235,600 tons and can host up to 5,734 guests, a figure that places it among the most populous passenger ships ever to sail.
Holding the size record meant Wonder carried the flagship role for the line until the Icon class arrived and moved the bar higher. The ship still stands as one of the most capacious vessels in the fleet, and its guest count exceeds that of the newer Icon ships. For anyone ranking cruise ships by passenger capacity rather than weight, it remains a standout entry in Royal Caribbean’s lineup.
5. Symphony of the Seas: Fourth Of The Oasis Four
Symphony of the Seas measures 228,081 gross tons, according to the ship’s Wikipedia entry. It took its maiden voyage on April 7, 2018, and carries 5,518 guests at double occupancy. Those figures place it comfortably above the 225,000-ton threshold used for this ranking.
The vessel belongs to the Oasis class, the family of ships that redefined what a cruise ship could look like by arranging open-air neighborhoods around a central promenade. Symphony was built as an enlargement of the earlier sisters, adding capacity while keeping the concept familiar to repeat travelers. It operates as a large-scale resort at sea, where the sheer number of venues means that no two days onboard need look alike.
6. Harmony of the Seas: The Slightly Bigger Third Sister
Harmony of the Seas arrived in 2016 as the third Oasis-class ship, weighing 226,963 tons. Per the Oasis class overview, the first two vessels of the class were slightly exceeded in size by this newer sibling.
That modest increase illustrates how cruise lines refine a successful design instead of reinventing it. Harmony kept the signature layout of the class while edging past its older sisters on tonnage, which was enough to take the title of the largest passenger ship at the time. Today it ranks mid-table among the eight vessels listed here, a reminder that even record-setting ships get overtaken as newer, larger designs are launched.
7. Oasis of the Seas: The Original Game Changer
Oasis of the Seas entered service in 2009 and gave its name to an entire class of megaships. According to the Oasis-class article, the original ship surpassed the earlier Freedom-class vessels as the world’s largest and longest passenger ships.
Its arrival changed expectations across the industry. Rather than a single stack of decks, the design opened a central park and boardwalk-style areas to the sky, creating distinct neighborhoods onboard. Later sisters expanded on that template, and the Icon class eventually grew beyond it. Even so, the first Oasis remains a landmark in cruise history, and the design it introduced continues to shape how Royal Caribbean plans its biggest ships more than fifteen years later.
8. Allure of the Seas: The Second Oasis Sister
Allure of the Seas entered service in 2010 and still lists at 225,282 gross tons, according to Royal Caribbean’s ship age table. It carries about 5,718 guests, making it the lightest vessel on this list yet still a ship that clears the 225,000-ton line.
As the second member of the Oasis class, Allure followed the pioneering design of the first ship and helped establish the formula as a lasting success rather than a one-off experiment. Its guest capacity is notably high, sitting just below the figure for Wonder of the Seas. More than a decade after its debut, the ship remains a major part of the fleet and a reminder of how large the line’s earlier megaships already were.
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