A 4-berth cabin is a room on a ship or a train designed to sleep exactly four people. The term "berth" refers to a built-in bed or bunk. In 2026 cruising, these cabins typically feature two lower twin beds (which can often be converted into a king) and two upper "pullman" beds that fold down from the ceiling or out of the wall. On overnight sleeper trains, a 4-berth "couchette" usually consists of two sets of bunk beds on either side of a small compartment. These cabins are the most popular choice for families or groups of friends traveling together, as they are the most cost-effective way to stay in a single unit. For 2026 travelers, it is a "pro-tip" to check if the cabin has a private bathroom (ensuite), as some older trains may still offer 4-berth compartments with shared facilities at the end of the hall, though on modern cruise ships, an ensuite is standard.