Budget Queen. If a cabin is not classified as a triple cabin, then you would have to change cabins. Then it depends on the current rates. You can't just add a 3rd person, to a double occupancy cabin.

Yes, you can add a third person to your Carnival cruise reservation, but it is not always a simple "tap and add" process. First, your specific cabin must have the physical capacity for a third guest, meaning it must be equipped with a sofa bed or a "Pullman" bunk that drops from the ceiling; many standard "double" rooms cannot legally accommodate more than two people. Second, you must consider the ship's legal lifeboat capacity; even if your room has an empty bed, the Coast Guard limits the total number of souls on board, so if the "zone" is at capacity, no new guests can be added. In 2026, adding a guest usually requires calling Carnival directly or your travel agent, as the website cannot always calculate the current market rate for the third passenger. You will be responsible for the additional cruise fare, port taxes, and daily gratuities. If your current room is at max capacity, you may be required to upgrade to a larger suite at the prevailing market rate.