Parents entering Mexico with their child (or children) must have a passport for the child or the child's birth certificate. A child entering (or leaving) Mexico with only one parent must have notarized consent from the absent parent. Similar consent is required if the child is traveling alone or with a non-parent. A notarized letter written by the absent parent is sufficient for Mexican immigration officials. A U.S. court order authorizing the travel will work if one parent refuses consent or cannot be located. A custody document will work in the event a minor is in the custody of one parent. Show a death certificate if one parent is deceased.
Mexico is a wonderful place for kids. Mexicans have a much more traditional take on families than we do in the States. It is not unusual for three, and even four, generations of a family to be living together in a single-family home or compound. Children are ubiquitous, with older children looking after their younger siblings. Mexican kids are curious about and accepting of foreigners.
Children from the United States living in Mexico have the opportunity to learn another language, and more importantly, to broaden their understanding of the world by experiencing a different culture firsthand. Parents of younger children will find a plethora of very well-trained and affordable baby-sitters and nannies. Older kids can be enrolled in Mexican public school anywhere in the country, or in a private bilingual school in certain cities.