The basic difference between each category code is the stateroom location and/or size of the room. The lower the number, the more desirable the cabin, in terms of size or location on the ship. As the numbers start to climb, you will find rooms further away from the mid-ship, as well as less square-footage.

Cruise room codes (also known as cabin category codes) are typically two-character alphanumeric strings that identify the type, size, and location of a stateroom. The first character usually denotes the general cabin class: for example, 'I' or 'P' for Inside, 'O' for Oceanview, 'B' for Balcony, and 'S' or 'A' for Suites. The second character often refers to the specific sub-category or location on the ship, such as deck height or whether the cabin is forward, aft, or midship. Midship cabins are often priced higher due to their stability and convenience, reflected in "higher" category codes. These codes are essential for reading deck plans, as they indicate specific amenities like obstructed views, extra-large balconies, or specialized themes like "Spa" or "Family" suites. Knowing these codes helps travelers understand exactly what they are paying for, as even similar-looking rooms can have different codes based on their proximity to elevators or the "splash" factor of lower decks.