If you turn 21 during a cruise in 2026, your "status" regarding alcohol consumption and gambling typically changes on the actual day of your birthday. Most major cruise lines, including Royal Caribbean and Carnival, establish the passenger's age at the time of sailing for stateroom assignments and infant policies, but they allow for the "aging up" of drinking privileges mid-voyage. Once the clock strikes midnight on your 21st birthday, you can visit Guest Services to have your "SeaPass" or room key updated to show you are now of legal age. This will unlock the ability to purchase alcohol in the bars and participate in all casino games (which sometimes require you to be 21, especially on Alaska or Hawaii routes). It is a great idea to bring a valid government-issued photo ID to Guest Services to confirm the change. However, keep in mind that the cruise line still reserves the right to refuse service if you have already been flagged for behavior issues as a minor earlier in the trip.