In 2026, the minimum age to check into a cruise depends largely on where the ship departs. For most cruises originating in North America (USA, Canada, Caribbean), major lines like Royal Caribbean and Carnival require at least one person in each cabin to be 21 or older. However, for sailings departing from Europe, Asia, South America, or Australia, the minimum age to sail unaccompanied or be the primary guest in a cabin is typically 18. This is a high-value distinction for young travelers planning a gap-year trip. It is a peer-to-peer essential to know that these rules can be waived for legally married couples (with proof) or active-duty military personnel. Regardless of the check-in age, the minimum drinking age on almost all North American lines remains a strict 21, even when the ship is in international waters, so be sure to check the "Alcohol Policy" of your specific cruise line before you pack your bags.