A Known Traveler Number (KTN) is a nine-digit number issued to individuals who have been approved to receive TSA PreCheck® expedited screening. The KTN must be added to the KTN field when booking airline travel reservations to have the TSA PreCheck® indicator appear on the boarding pass. The KTN is issued to members approved for the TSA PreCheck® Application Program, Global Entry, NEXUS, or SENTRI. For members approved for the TSA PreCheck® Application Program, the KTN is a combination of numbers and letters and typically begins with TT for those who enrolled through IDEMIA or TE for those who enrolled through Telos, both of which are official TSA PreCheck® enrollment providers. For members approved for Global Entry, NEXUS, or SENTRI, the KTN is the CBP PASS ID number, which usually begins with 10, 13, 14, 15, 16, 50, 70, 80, 95, 98, or 99 and can be found on the back of the NEXUS, SENTRI, or Global Entry card in the upper-left corner or by logging on to the Trusted Traveler Programs website.

The KTN is used to add the TSA PreCheck® indicator to the boarding pass, which allows travelers to use TSA PreCheck® lanes for expedited airport screening. Travelers must include the KTN in the ‘KTN field of each reservation made with a participating airline, which can be done when booking reservations online via a participating airline website, by phone with an airline reservation agent, or with the travel management company making reservations. The KTN can also be saved to any frequent flyer profiles, employer booking systems, or online travel websites that travelers use.

If a traveler forgets their KTN, they can look it up on the TSA website if they are a member of the TSA PreCheck® Application Program or on the Trusted Traveler Program website if they are a member of another trusted traveler program. If a traveler is unable to find their KTN, they can call Homeland Security at 855-347-8371 for assistance.