Flying Into/Out of Mexico US citizens of any age flying to or from Mexico must have a US passport book, no exceptions.

No, a 16-year-old cannot travel to Mexico by air without a valid Passport Book. While the Western Hemisphere Travel Initiative (WHTI) allows U.S. citizens under 16 to use just an original birth certificate for land and sea crossings (like driving across the border or a closed-loop cruise), this exception ends on a child's 16th birthday. Once a traveler turns 16, they are legally considered an adult for international documentation purposes and must present a valid Passport Book or Passport Card for all land and sea entries. For any travel by air, a Passport Book is the only acceptable document regardless of age. Furthermore, because a 16-year-old is still a minor, it is a high-value peer tip to carry a notarized Letter of Consent signed by both parents if they are traveling alone, with a friend, or with only one parent. Mexican immigration officials are increasingly strict in 2026 about verifying that minors have parental permission to travel to prevent child custody disputes and human trafficking, so having this extra document can prevent significant delays at the border.