If you are traveling to Mexico with minors and you are NOT a parent or legal Guardian.
The Mexican National Immigration Institute (INM) requires special documentation with regard to minor (under 18 years of age) travel if:

  • The minor is departing Mexico (i.e. not entering);
  • The minor is traveling by air or sea;
  • The minor is traveling alone or with someone other than a parent or legal guardian who is of legal age (grandparent, uncle/aunt, school group leader, etc.); and
  • The minor is using Mexican documents to travel (birth certificate, passport, temporary or permanent Mexican residency).

Here is a Sample Form

visit: https://photos.state.gov/libraries/mexico/1019454/arevaloya/sampleMinorTravelConsent_001.pdf