Whether a teen needs TSA PreCheck depends on whether they are traveling with an enrolled parent or guardian and their age. Children under 12 with an eligible adult can join them in the TSA PreCheck lane without applying. Children aged 13 to 17 on the same reservation as an enrolled parent or guardian may also access the PreCheck lanes provided they have an indicator on their boarding pass. However, they may be randomly excluded from having an indicator on their boarding pass, which means they will need to go through standard security screening. Children 17 and under traveling alone will need to apply for TSA PreCheck.