Today's cruise ships are larger than ever, but have you ever wondered which ones are the biggest?
The "largest" cruise ship can be subjective, depending on whether you measure by gross tonnage, length, or height. Regardless, modern mega-ships are impressive and are sure to turn some heads in person.
Size isn’t just about bragging rights, either. Larger ships offer a shocking number of onboard amenities, entertainment, and dining options that rival small cities. The towering passenger decks, expansive sun decks, and top-notch accommodations are meant to impress in scale and experience.
As of March 2026, Royal Caribbean International holds the record for the biggest, longest, and tallest cruise ships at sea. Its Icon Class vessels, including the Icon of the Seas and Star of the Seas, measure over 1,196 feet long, weigh more than 248,000 gross tons, and can carry over 7,000 passengers, along with 1,350 crew members, at maximum capacity.
However, it might surprise you to learn that its tallest cruise ships aren't part of its record-breaking Icon or Oasis Classes. Instead, the tallest cruise ship at sea is a Quantum Class vessel.
Here's an in-depth look at the world's biggest, longest, and tallest cruise ships.
What is the biggest cruise ship in the world?
If going by gross tonnage, which measures the total internal volume of a ship rather than its weight, the largest cruise ship in the world is Star of the Seas — along with her younger sister, Icon of the Seas. Both of these massive vessels come in at 248,663 gross tons, making them the two largest cruise ships in the world.
Star of the Seas entered service in 2025 and sails to the Eastern and Western Caribbean from Port Canaveral (Orlando), Florida. Icon of the Seas' maiden voyage took place in January 2024. She currently sails from Miami, Florida, but will relocate to Galveston in 2027.
Highlights include the record-breaking Category 6 Waterpark, indoor AquaTheater, AquaDome food hall, elegant supper club, redesigned suite sun deck, the largest ice skating rink at sea, family-friendly Surfside Neighborhood, infinite verandah staterooms, and more.
A third Icon Class ship — Legend of the Seas — will join the Royal Caribbean fleet in July 2026. She'll begin her career in Europe before repositioning to Fort Lauderdale. Legend will then return to Europe in May 2027, giving cruisers the chance to combine an epic onboard experience with culturally rich destinations like Barcelona, Spain; Marseille, France; and Naples, Italy.
Read more: Top 5 Largest Royal Caribbean Ships: Why Size Matters
How long is the longest cruise ship?
It just so happens that the biggest cruise ships are also the longest. Star of the Seas and Icon of the Seas measure a whopping 1,196 feet, or 364 meters, long.
Close behind are Royal Caribbean's Oasis Class vessels. These six ships measure anywhere from 1,187 to 1,188 feet long. As such, they were the world's biggest and longest cruise ships from 2009 until 2024.
In comparison, the Empire State Building is 1,454 feet tall to the very tip of its antenna, while the Eiffel Tower is 1,083 feet tall. This means that, while modern-day cruise ships aren't as tall as the iconic skyscraper in New York City, Oasis and Icon Class ships are longer than the Eiffel Tower — if you were to stand them upright.
Read more: Top 25 Biggest Cruise Ships in the World
What is the tallest cruise ship?
Although Icon Class ships are the world's biggest and longest at sea, they aren't the tallest. That record goes to Odyssey of the Seas, which reaches a height of around 300 feet above sea level from the keel to the very top of its superstructure.
This is, in part, thanks to the North Star glass observation capsule, which holds the Guinness World Record as the tallest viewing deck on a cruise ship.
Not only that, but the ship's structure itself is roughly 236 feet high from the waterline to the top of the ship. Combined with the 28-foot draft, Odyssey has a total structural height of over 260 feet.
Other than her height, Odyssey is a mid-sized cruise ship, measuring 167,704 gross tons and 1,138 feet long. As such, Odyssey offers a different kind of onboard experience.
Instead of record-breaking waterparks, awe-inspiring AquaTheaters, and sprawling pool decks, Odyssey of the Seas focuses on innovative attractions and breathtaking views — think 270-degree panoramic windows, high-tech bars, stunning adult-only Solarium, and more.
