A Guarantee stateroom (GTY) is one where there is no stateroom number assigned at the time of booking. A stateroom may be assigned any time after final payment has been received, up to the day of sailing. A Guarantee stateroom guarantees you a stateroom in the category you have paid for (Inside, Oceanview etc.).

On a Norwegian Cruise Line (NCL) booking, GTY stands for "Guarantee." When you book a GTY cabin, you are choosing a specific category of room (such as Inside, Oceanview, or Balcony) at a discounted rate, but you are giving up the right to select your specific cabin number or location on the ship. NCL guarantees that you will receive a room in the category you paid for—or potentially a higher one as a free "upgrade"—but your actual room assignment might not be revealed until a few weeks, or even a few days, before the ship sails. This is a strategic choice for budget-conscious travelers who don't mind where they are on the ship. The risk is that you could end up in a less desirable location, such as directly under a noisy nightclub, near a heavy-traffic elevator bank, or at the very front of the ship where motion is more palpable. However, the financial savings are often significant, and for many, the "gamble" of a GTY stateroom is worth the lower price, especially since the actual room amenities remain identical to those of non-GTY cabins in the same class.