No. A child under 16 must appear in person for every U.S. passport application, including a renewal, so a child’s passport cannot be renewed by mail.
Federal passport rules in 22 CFR 51.28 require minors under 16 to apply in person unless a senior passport authorizing officer specifically excuses the appearance. Both parents or each legal guardian must sign the application on the child’s behalf, whether it is a first passport or a renewal, and must provide evidence of parentage showing the child’s name, date and place of birth, and the parents’ names. One parent can apply alone with a notarized statement of consent from the other parent, or with proof of sole custody, such as a court order, an adoption decree, or the other parent’s death certificate. Teens aged 16 and 17 must also appear in person, although they may sign their own application. Under 22 CFR 51.4, a passport issued to a child under 16 is valid for only five years, compared with ten years for applicants 16 and older, so families repeat the in-person process more often.
Source: 22 CFR 51.28, Minors (Electronic Code of Federal Regulations)
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