Renewal by mail is only for adult passport renewals.  When applying by mail, carefully read all the instructions to make sure your application is complete and correct before you send it to the Embassy. 

You may renew your passport by mail if your most recent U.S. passport:

• is undamaged and can be submitted with your application;
• was issued within the last 15 years;
• was issued with 10-year validity; and
• was issued in your current name [or you have changed your name and can submit legal documentation (such as a marriage certificate or legal change of name) to prove this change.

If you do not meet each requirement, you will need to appear in person with an appointment at the Embassy.  Follow this link for instructions to renewal in person.