Largest Cruise Ships Ever Built: Top 10

The largest cruise ships ever built are three Icon-class sisters of 248,663 gross tons each as of October 2026, led by Royal Caribbean's Icon of the Seas.

This Finepedia guide, written in October 2026, ranks the ten biggest cruise ships now sailing by gross tonnage, a measure of a ship's enclosed volume rather than its weight. Every one of the top nine belongs to Royal Caribbean International, and the newest, Legend of the Seas, joined the fleet in the summer of 2026. Only one ship from another line, MSC World America, makes the list. For more ships and places to stay, see the Finepedia guides Most Famous Cruise Ships in the World: Top 10 and Biggest Hotels in the World: Top 10.

How We Chose These

We ranked ships in service as of October 2026 by gross tonnage (GT), using figures from ship registers such as DNV and Bureau Veritas as listed by Wikipedia, and checked them against cruise line fact sheets and cruise news sites. Where ships share the same tonnage, we placed them in the order they entered service. Ships still being built, and ocean liners such as Queen Mary 2, which is smaller, are not included. Passenger numbers are given at double occupancy, meaning two guests per cabin, unless stated.

The 10 Largest Cruise Ships at a Glance

1. Icon of the Seas Started a New Era of Giant Ships

Icon of the Seas took the record as the biggest cruise ship afloat when it made its first trip from Miami on 27 January 2024. Meyer Turku in Finland built the ship, which has 20 decks and room for 5,610 guests two to a cabin, or about 7,600 when every berth is full, served by around 2,350 crew. Royal Caribbean says it has the biggest waterpark of any cruise ship, along with the tallest waterfall and water slide at sea.

Key Facts

• Gross tonnage: 248,663
• Entered service: January 2024, from Miami
• Guests: 5,610 at double occupancy, about 7,600 at most
• Fuel: can run on liquefied natural gas (LNG)

Did You Know?

Icon of the Seas measures about 365 m, or 1,198 ft, longer than three football pitches placed end to end. Its LNG engines cut some pollution, but environmental groups argue that methane leaking from the fuel can harm the climate.

2. Star of the Seas Brought the Icon Design to Florida's Space Coast

Star of the Seas, the second ship of the Icon class, came from the same Finnish shipyard and shares the exact tonnage of its older sister. It began sailing on 16 August 2025 from Port Canaveral, near the Kennedy Space Center, on trips to the Caribbean. Like Icon, it is laid out in eight themed areas, from a waterpark called Thrill Island to a glass-domed space at the front of the ship.

Key Facts

• Gross tonnage: 248,663
• Entered service: August 2025, from Port Canaveral
• Decks: 20
• Shows: a stage version of Back to the Future, an ice show and acrobatics in an outdoor theatre

Why It Matters

Having two ships of this size based on opposite coasts of Florida let Royal Caribbean offer its largest design to many more holidaymakers, and it showed how strongly the cruise business had bounced back after the pandemic.

3. Legend of the Seas Is the Newest Giant

Legend of the Seas, the third Icon-class ship, was handed over by Meyer Turku in June 2026 and set off on its first cruise on 4 July 2026 from Civitavecchia, the port for Rome. After a summer in the Mediterranean, it moves to Fort Lauderdale in Florida from November 2026. At 364.84 m it is a fraction longer than its two sisters, about 30 cm on the register, though its tonnage is the same.

Key Facts

• Gross tonnage: 248,663
• Entered service: July 2026, from Civitavecchia, Italy
• Cabins: 2,805
• Guests: 5,610 at double occupancy, about 7,600 at most

Did You Know?

Legend is the first Icon-class ship to start its career in Europe. Its sisters both began in Florida, which is the heart of Royal Caribbean's business.

4. Utopia of the Seas Is the Biggest of the Oasis Class

Utopia of the Seas is the sixth and largest member of the Oasis class, at 236,473 GT. Chantiers de l'Atlantique built it in Saint-Nazaire, France, and it began sailing on 19 July 2024 from Port Canaveral. It mainly runs short three- and four-night trips to the Bahamas.

Key Facts

• Gross tonnage: 236,473
• Entered service: July 2024, from Port Canaveral
• Builder: Chantiers de l'Atlantique, Saint-Nazaire, France
• Fuel: the first Oasis-class ship able to run on LNG

Why It Matters

Utopia showed that even an older design can be updated with cleaner fuel. In February 2025 it changed course to salute the historic liner SS United States, then under tow to Alabama, where it was to be sunk as an artificial reef.

5. Wonder of the Seas Held the Record for Two Years

Wonder of the Seas held the size record from its first voyage in March 2022 until Icon of the Seas arrived in January 2024. It was built in Saint-Nazaire and is about 362 m long. It can carry 5,734 guests at double occupancy, or close to 7,000 when full, with a crew of about 2,300.

Key Facts

• Gross tonnage: 235,600
• Entered service: 2022
• Guests: 5,734 at double occupancy, about 6,988 at most
• Crew: about 2,300

Did You Know?

Wonder's open-air Central Park is planted with over 10,000 plants, and its zip line stretches across a gap ten decks high.

6. Symphony of the Seas Is Longer Than Any Aircraft Carrier

Symphony of the Seas, number four in the Oasis class, became the biggest cruise ship afloat when it came out of Saint-Nazaire in 2018. At about 361 m long, it beats the U.S. Navy's Nimitz-class aircraft carriers by roughly 30 m. It carries 5,518 guests at double occupancy and around 2,200 crew.

Key Facts

• Gross tonnage: 228,081
• Entered service: 2018
• Guests: 5,518 at double occupancy, about 6,680 at most
• Restaurants: 22

Why It Matters

Symphony was built to use about a quarter less fuel than the first Oasis-class ships, partly by using LED lighting and by turning waste engine heat into power, showing how each new ship of the class was made more efficient.

7. Harmony of the Seas Was Built in 32 Months

Harmony of the Seas, the third Oasis-class ship, sailed out of the Saint-Nazaire yard on 15 May 2016 as some 70,000 people watched, after 32 months of building. Its first cruise left Southampton in England on 29 May 2016, and it spent its first summer based in Barcelona. It has 2,747 cabins for 5,479 guests at double occupancy.

Key Facts

• Gross tonnage: 226,963
• Entered service: May 2016, from Southampton
• Cabins: 2,747
• Builder: STX France, today called Chantiers de l'Atlantique

Did You Know?

Harmony pumps a carpet of tiny air bubbles under its hull, which lets it slip through the water more easily and saves around 7 to 8 percent of its fuel.

8. Oasis of the Seas Was the First of the Mega Ships

Oasis of the Seas, launched in 2009, was the first ship of the Oasis class and the first cruise ship over 220,000 GT. Unlike the later ships, it was built in Turku, Finland, and made its first cruise on 5 December 2009. Its idea of dividing a ship into seven neighbourhoods, including an open-air park in the middle, changed how big cruise ships are designed.

Key Facts

• Gross tonnage: 226,838
• Entered service: December 2009
• Builder: STX Europe, Turku, Finland
• Neighbourhoods: seven, including Central Park and the Boardwalk

Why It Matters

Oasis showed that people would book a ship as a holiday place in itself, not just as a way to visit ports. Its success led to five more ships of the same class over the next 15 years.

9. Allure of the Seas Is a Near Twin of Oasis

Allure of the Seas sailed from Turku on 29 October 2010 and headed for its home port near Fort Lauderdale, Florida. It was built to the same plans as Oasis of the Seas, and for years the two shared the size record. A refit in 2020 added the Ultimate Abyss dry slide and new water slides.

Key Facts

• Gross tonnage: 226,637
• Entered service: December 2010
• Builder: STX Europe, Turku, Finland
• Length: about 360 m

Did You Know?

Allure is reported to be about 50 mm longer than Oasis, even though both followed the same design. The shipyard said such tiny gaps can come from the temperature of the steel during building.

10. MSC World America Is the Biggest Ship Outside Royal Caribbean

MSC World America is the largest cruise ship not owned by Royal Caribbean. The French yard Chantiers de l'Atlantique built it for MSC Cruises, and it was named in Miami on 9 April 2025 and sails to the Caribbean. It is about 333 m long and 47 m wide, can carry up to about 6,760 guests and has around 2,140 crew. Its stern opens into a Y shape around an outdoor promenade.

Key Facts

• Gross tonnage: 216,638
• Named: 9 April 2025, in Miami
• Builder: Chantiers de l'Atlantique, Saint-Nazaire, France
• Fuel: LNG

Why It Matters

Just behind it are its older sister MSC World Europa, at about 215,863 GT, and Disney Adventure, at about 208,108 GT, which began sailing in Asia in March 2026. That shows rival lines are now building ships close to Royal Caribbean's size.

Frequently Asked Questions

What does gross tonnage mean?

Gross tonnage is not weight. It is a number worked out from the volume of all the enclosed spaces on a ship, which is why it is the usual way to compare the size of cruise ships.

Are even bigger ships being built?

Yes. Royal Caribbean has ordered more Icon-class ships, and a seventh Oasis-class ship is also on order, while MSC is building more World-class ships through about 2031.

Conclusion

The largest cruise ships ever built are floating towns, each carrying more than 5,000 guests and thousands of crew. Royal Caribbean holds the first nine places, with its Icon-class trio sharing the top spot, while MSC World America shows that other lines are catching up. Ship sizes have more than doubled since the late 1980s, and new giants are already on order. To read more, see the Finepedia guides Most Famous Cruise Ships in the World: Top 10 and Biggest Hotels in the World: Top 10.