3. Royal Bay. Cruise vacations are all about once-in-a-lifetime experiences, and Royal Bay totally lives up to that reputation. Featuring over 40,000 gallons of water, it's the largest pool at sea.

The size of a Royal Caribbean pool varies significantly by ship class, but they are designed to be some of the most expansive water features at sea. On Icon-class ships (the largest in the world), the Royal Bay Pool is the largest pool ever built on a cruise ship, containing over 40,000 gallons of water and covering more than 5,800 square feet. For those on Oasis-class ships, the main pools are typically around 15 to 20 feet wide and 40 to 50 feet long, with depths ranging from 3.5 to 5 feet. Beyond standard swimming pools, Royal Caribbean is famous for the AquaTheater, a specialized deep-water pool used for high-diving shows that reaches a depth of nearly 18 feet. In 2026, the fleet's focus is on "neighborhood-specific" water features, such as the infinity-edge Hideaway Pool on Icon of the Seas, which provides a beach-club atmosphere. While individual pools may not reach Olympic dimensions, the sheer volume of water—spread across multiple pools, whirlpools, and the "Category 6" waterpark—ensures that these mega-ships offer a massive total aquatic footprint for thousands of passengers.