Do you need a passport to go to Canada or Mexico?

The rule depends on how you cross. For air travel to and from Canada or Mexico, a US citizen needs a valid passport book, with no exceptions for the passport card or other documents. For land and sea crossings, the Western Hemisphere Travel Initiative permits alternatives: the passport card, which is a wallet-sized document valid only for land and sea entry from Canada, Mexico, the Caribbean, and Bermuda, an enhanced driver's license issued by a handful of states, or a trusted traveler card such as NEXUS, SENTRI, or Global Entry. A standard driver's license alone is not sufficient for adults.

Children under 16 have relaxed requirements at land and sea borders and can present a birth certificate, and the same applies to those under 19 travelling in organized groups. Non-citizens, including permanent residents, follow different rules and should check both the destination's entry requirements and what they need to re-enter the United States. Mexico has its own entry procedures beyond the border zone, and Canada can deny entry to travellers with certain criminal records including a single DUI conviction, which surprises people every year.

Two practical notes. Cruise passengers on closed-loop itineraries departing and returning to the same US port can technically sail with a birth certificate and government ID, but a passport is strongly advised because anyone who must fly home from a foreign port mid-cruise, after an illness or missed ship, cannot do so without one. And passport validity matters: while Canada and Mexico do not enforce a six-month validity rule the way many countries do, airlines sometimes apply blanket policies, and a renewal takes weeks, which is the reason to check the expiration date well before booking rather than at the airport.