Entry into Canada: Canadian law requires that all persons entering Canada carry proof of citizenship and identity. A valid U.S. passport, passport card, or NEXUS card satisfies these requirements for U.S. citizens. Children under 16 only need proof of U.S. citizenship.

For domestic flights within Canada, a 12-year-old technically does not need a photo ID to board a plane when traveling with an adult, but it is highly recommended to carry some form of identification. According to Public Safety Canada, the strict requirement for government-issued photo ID (like a passport or driver's license) only applies to passengers who appear to be 18 years of age or older. However, airlines like Air Canada and WestJet strongly advise that children carry a birth certificate, a non-photo government ID, or even a student card to verify their age and identity, especially if they appear older than they are. If a 12-year-old is traveling as an Unaccompanied Minor, the airline will require official proof of age and identity. For any international travel, including flights between Canada and the United States, a valid passport is mandatory for all children, regardless of age. Always verify with your specific airline, as they may have internal policies that are more stringent than the general government regulations.