The Royal Caribbean Oasis of the Seas and her sister ship the Allure of the Seas, are the world's largest cruise ships for two more months--until their sister ship, the Harmony of the Seas launches in May 2016. These two resort-style mega-ships feature many exciting onboard activities, entertainment, and dining options.

Until the Carnival Vista is launched in May 2016 , the Carnival Breeze  is Carnival Cruise Line's largest ship.The 3,690-passenger, 130,000-ton ship has many features that past, present, and future Carnival cruise fans love. The ship's decor is a little softer and more toned-down than some of the other ships in the fleet, but the Carnival Breeze delivers the same fun-in-the-sun (and on the sea) memorable vacations.

Carrying over 3,000 guests, the Celebrity Reflection is Celebrity Cruises' largest cruise ship, joining her four older sister ships (Celebrity Solstice, Celebrity Equinox, Celebrity Eclipse and Celebrity Silhouette) in the fall of 2012. Celebrity has kept many of the features found on the other Solstice class ships, but has added a few new ones that large cruise ship travelers will enjoy.

Those who have sailed on the Regal Princess' sister ship the Royal Princess will be delighted to know that this ship looks very much the same, with just a few modifications. This is a terrific large cruise ship, carrying almost 3,600 guests.