Passport requirements changed for all U.S. travelers in 2009, and the requirements for people on cruises became very complicated. Your need for a passport depends on where you embark from, where you return from, and whether it is a one-way or round-trip cruise.
A passport is needed for all cruises that stop in Africa, South America, Asia, Europe, Australia and Antarctica.
If you are on a one-way cruise that embarks in the U.S. and ends in a foreign country, requiring you to fly back, you must have a passport. Similarly, if you are flying to your embarkation city in a foreign country, you must have a passport.
If your cruise begins and ends in the same U.S. city and is traveling to Canada, Bermuda, the Caribbean or Mexico, it is considered a closed loop and no passport is needed, but you must carry a government-issued ID, such as a driver's license.
Cruises that originate in and return to Hawaii or U.S. territories do not require a passport.
Even if your cruise does not require a passport, have one in case you miss embarkation and must fly to the next port or if an emergency requires you to fly home.