Ships today, mega ships as they are known, are as big as some aircraft carriers. But how big are they and how do we measure them?
Cruise ships are evaluated based on their gross tonnage (gt), which despite its name is a volume calculation, basically how much inside space on a ship.
Royal Caribbean continues to dominate the top spots for the biggest ships, coming in around 228 thousand gt in size. For context, the Titanic was a mere 46,329 gt, which means you could fit almost 5 Titanics in today’s biggest ship.
Here's a look at the 20 biggest cruise ships currently sailing throughout the world.
1. Symphony of the Seas, Royal Caribbean

Length: 1,188 feet
Width: 215.5 feet
Passengers: 5,518 double occupancy (d/o)
Symphony of the Seas, along with other Oasis-class ships leads the top of the list. One key metric, it is significantly wider (50 % plus) than its competition, contributing to its large size.
Sailing out of Miami, Symphony of the Seas visits ports in the eastern and western Caribbean throughout the year. For 2023, it will offer itineraries in Europe.
2. Harmony of the Seas, Royal Caribbean

Gross Tonnage: 226,963
Length: 1,188 feet
Width: 215.5 feet
Passengers: 5,479 d/o
Sailing out of both Miami and Port Canaveral (Orlando), it visits popular ports throughout the Caribbean, also offering southern itineraries to the ABC islands (Aruba, Bonaire and Curacao.)
Just marginally smaller than the Symphony of the Seas, it features the Ultimate Abyss, a 10 story water slide, which hangs off the side of the ship.
3. Oasis of the Seas, Royal Caribbean

Gross Tonnage: 226,838
Length: 1,187 feet
Width: 215 feet
Passengers: 5,602 d/o
Oasis of the Seas offers cruises from both Miami and New Jersey, sailing to the Caribbean and picturesque Eastern Canada.
Still a giant among cruise ships, it was the first ship at sea to have a zip line. With a length of 82 feet, it has a great view of the Boardwalk 9 decks below.
4. Allure of the Seas, Royal Caribbean

Gross Tonnage: 225,282
Width: 215 feet
Passengers: 5,484 d/o
For much of 2022, Allure of the Seas will be homeporting in Fort Lauderdale, sailing throughout the Caribbean. With the new cruise port in Galveston, Texas, Allure of the Seas will then move there, serving the western Caribbean.
Fun fact, Allure and Oasis of the Seas were designed to be the same size, however once complete, the shipyard noticed that Allure was two inches longer. Oops.
5. Costa Smeralda, Costa Cruises

Gross Tonnage: 185,010
Length: 1,106 feet
Width: 138 feet
Passengers: 5224 d/o
This Italian cruise line (owned by Carnival) is inspired by the dolce vita and carefree cruising. lt is named for Smerelda, a well known tourist area in Sardinia, Italy.
It sails from Savona, Italy, Barcelona and Palma de Mallorca to sun soaked ports in the Mediterranean.
6. Iona, P&O Cruises

Gross Tonnage: 184,089
Length: 1,130 feet
Width: 138 feet
Passengers: 5,250 d/o
Residing in Southampton, Iona sails throughout Europe and the Canary Islands.
P&O is a British cruise line owned by Carnival Corporation. Iona, biggest in the fleet, has its own gin distillery onboard and is named after the Sottish Island of Iona, which was decided upon in a public contest.
7. AIDAnova, AIDA Cruises

Gross Tonnage: 183,858
Length: 1,106 feet
Width: 138 feet
Passengers: 5,252 d/o
AIDAnova sails from both Tenerife in the Canary Islands along with Rotterdam and Hamburg, touring several islands and parts of Europe.
A German cruise line that has been in operation the 1960s, it is now owned by Carnival Corporation.
8. AIDAcosma, AIDA Cruises

Gross Tonnage: 183,858
Length: 1106 feet
Width: 138 feet
Passengers: 5,228 d/o
This brand new ship calls Hamburg, Abu Dhabi, Palma de Mallorca, Barcelona, and Rotterdam home. It sails throughout Europe and the Middle East.
It uses a combination of two energy sources - liquefied natural gas (LNG) and traditional fuel oil to be more efficient.
9. MSC Virtuosa, MSC Cruises

Gross Tonnage: 181,541
Length: 1,087 feet
Width: 141 feet
Passengers: 4,842 d/o
MSC Virtuosa sails from numerous ports in the Middle East and Europe including Dubai, Abu Dhabi, Doha, Naples, Genoa, Marseille, Barcelona and Southampton, with itineraries throughout the Middle East and Europe.
One of MSC’s newer cruise ships, it set sail in 2021 and is one of the most energy efficient at sea.
10. MSC Grandiosa, MSC Cruises

Gross Tonnage: 181, 541
Length: 1,094 feet
Width: 141 feet
Passengers: 4,842 d/o
MSC Grandiosa sails and visits ports throughout Europe including Italy, France, Spain, Denmark, Germany, Russia and Malta.
MSC Cruises is a Swiss-Italian cruise line formed in 1989. It is the world’s biggest privately owned cruise line.
11. Mardi Gras, Carnival Cruises

Gross Tonnage: 180,000
Length: 1,130 feet
Width: 137 feet
Passengers 5,282
Carnival continues the fun with Mardi Gras, named after the first ship in the fleet, TSS Mardi Gras. Its sails from Port Canaveral (Orlando) to ports in the Caribbean.
This ship boasts the first roller coaster at sea, along with a number of celebrity chef dining venues such as Guy Fieri and Emeril Lagasse.
12. MSC Meraviglia, MSC Cruises

Gross Tonnage: 171,598
Length: 1,034 feet
Width: 141 feet
Passengers: 4,488 d/o
Homeports include Port Canaveral (Orlando), Barcelona, Cannes Genoa, Rome and Palma de Mallorca, sailing throughout the Caribbean and Europe,
Its godmother is the legendary Italian actress Sophia Loren which ties nicely to the ship’s name, Meraviglia, which means wonder in English.
13. Spectrum of the Seas, Royal Caribbean

Gross Tonnage: 169,379
Width: 135 feet
Passengers: 4,246 d/o
Sailing from Singapore, Beijing and Shanghai, China, Spectrum of the Seas visits a number of ports throughout Asia including China, Japan, Malaysia, Thailand and Vietnam.
Designed for the Asian market, it has several upscale offerings, such as a one of a kind suite area that includes private elector access, shopping and lounges.
14. Odyssey of the Seas, Royal Caribbean

Gross Tonnage: 169,300
Length: 1,138 feet
Width 135 feet
Passengers: 4,284 d/o
Royal Caribbean’s newest ship sails from Fort Lauderdale and will move to Rome in 2022 for itineraries that feature Europe, Turkey and Israel.
The ship was recently launched in 2021 and offers innovative features like Zone Zero, the ultimate virtual reality experience.
15. Norwegian Encore, Norwegian Cruise Line

Gross Tonnage: 169,116
Length: 1,094 feet
Width: 136 feet
Passengers: 3,998 d/o
With ports in Seattle, Miami and Los Angeles this ship gets around, venturing to Alaska, Canada, Caribbean, Panama Canal, Central America, and California.
It was the winner of Best New Ship, Porthole Cruise Magazine 2020 Editor-in-Chief Awards.
16. Ovation of the Seas, Royal Caribbean

Note: this is a tie with Anthem of the Seas and Quantum of the Seas
Gross Tonnage: 168,666
Length: 1,138 feet
Width: 136 feet
Passengers: 4,180 d/o
Ovation of the Seas is the jet setter of cruise ships with homeports in Seattle, Vancouver, Sydney, Oahu and Hawaii.
It travels long voyages, visiting Alaska, Australia, New Zealand, South Pacific, Hawaii and Canada.
17. Anthem of the Seas, Royal Caribbean

Gross Tonnage: 168,666
Length: 1,141 feet
Width: 136 feet
Passengers: 4,180 d/o
This transatlantic ship ports in Southampton, as well as Cape Liberty, New Jersey.
It sails to England, France, Caribbean, Norway and the Canary Islands,
18. Quantum of the Seas, Royal Caribbean

Gross Tonnage: 168,666
Length: 1141 feet
Width: 136 feet
Passengers: 4,180 d/o
Another international traveler, Quantum of the Seas’ home bases are Brisbane, Australia, Vancouver, and Seattle.
It sails to Australia, Alaska, Canada, South Pacific and Hawaii.
19. Norwegian Bliss, Norwegian Cruise Line

Gross Tonnage: 168,028
Length: 1,084 feet
Width: 136 feet
Passengers: 4,004 d/o
Homeports include Seattle, Los Angeles and Quebec City, sailing to a number of destinations including Alaska, Canada, Mexico, Central America, and the Panama Canal.
This ship was designed for Alaskan cruises, with great observation venues to maximize the experience.
20. Norwegian Joy, Norwegian Cruise Line

Gross Tonnage: 167,725
Length: 1,094
Width: 136 feet
Passengers : 3,804 d/o
Homeports include New York, Miami, Los Angeles, Port Canaveral (Orlando) with a number of sailings to Bermuda, Caribbean, Mexico, Central America, Panama Canal and Canada.