Yes, in 2026, a valid passport is strongly recommended for almost all cruises, and a visa may be required depending on your citizenship and the ports of call. For U.S. citizens on "Closed-Loop" cruises (starting and ending at the same U.S. port), you can technically still travel with just a birth certificate and a government-issued photo ID (like a REAL ID), but this is risky; if you are forced to fly home from a foreign port due to an emergency, you cannot board a plane without a passport. For all international itineraries (Europe, Asia, etc.), a passport with at least 6 months of validity is mandatory. Regarding visas, in late 2026, Americans and many other nationalities will need an ETIAS authorization to cruise in Europe. Some destinations like China, Vietnam, or Australia require specific e-visas or paper visas that must be obtained weeks in advance. Many cruise lines (like Royal Caribbean or NCL) will help facilitate "on-arrival" visas for certain ports (like Egypt), but the ultimate responsibility for having the correct documentation rests with the passenger.