Whether you can gamble at 18 on a cruise ship depends entirely on the cruise line's specific policy and the ship's current location. In 2026, major lines like Royal Caribbean, Carnival, and MSC generally allow passengers aged 18 and over to gamble in the onboard casino while the ship is in international waters. However, there is a significant exception for cruises that depart from or visit Alaska or certain U.S. ports, where the legal gambling age is strictly 21. For example, Disney Cruise Line does not have casinos at all, while lines like Celebrity and Princess often maintain an 18+ policy for most international itineraries but raise it to 21 for North American coastal sailings. It is also important to note that while you might be allowed to gamble at 18, the legal drinking age on most U.S.-based ships remains 21 regardless of where the ship is located. Always check the "Guest Conduct Policy" in your cruise app before you sail to ensure you are aware of the age limits for your specific itinerary.