Known Traveler Number: What is it, and why should you have one?

Whenever you book travel, there are probably a few key pieces of information — like a flight confirmation number, passport details and airline login credentials — that you like to keep handy.But if you're a member of TSA PreCheck or Global Entry, there's another key piece of information you should always have at the ready: your Known Traveler Number.That nine-digit code is your ticket to the TSA PreCheck lanes. And it's often the thing that's missing if you ever check in for a flight and find your boarding pass doesn't have the "TSA PreCheck" mark.Here's what to know about getting a KTN, how to find it and how to make sure it's attached to your flight reservations.A Known Traveler Number, or KTN, is a special code that's assigned to every TSA PreCheck and Global Entry member.It's often a jumble of numbers and letters, sort of like a frequent flyer number or confirmation number.But it's not assigned by an airline. Rather, it's from the U.S. Department of Homeland Security.It proves you're an approved, vetted member of TSA PreCheck, Global Entry or one of the other federal Trusted Traveler Programs, such as Nexus or SENTRI.And it shows the TSA that you're eligible to use the TSA PreCheck lanes at U.S. airports.Reward your inbox with the TPG Daily newsletterJoin over 700,000 readers for breaking news, in-depth guides and exclusive deals from TPG’s expertsBy signing up, you will receive newsletters and promotional content and agree to our Terms of Use and acknowledge the data practices in our Privacy Policy. You may unsubscribe at any time.Travelers with a KTN have gone through an application and screening process, and they are known and recognized as frequent travelers by the U.S. government.Passengers proceed through the TSA security checkpoint at Denver International Airport (DEN) in August 2019. ROBERT ALEXANDER/GETTY IMAGESShould you apply for a Known Traveler Number?Getting a KTN is helpful for air travel because it means you're a member of a program that offers shorter wait times.A KTN is your key to accessing TSA PreCheck lanes, which typically have shorter security wait times.Ditto for Global Entry, which offers a fast-track through passport control after an international flight. A Global Entry membership also gets you TSA PreCheck access.How to get a KTNThere are several ways to obtain a KTN through various Trusted Traveler programs run by DHS.Each program requires travelers to submit an application and go through an interview process. Those interviews generally occur in person at enrollment centers for first-time applicants. Many of those enrollment centers are at airports.A Global Entry Enrollment on Arrival lane at Washington's Dulles International Airport (IAD). SEAN CUDAHY/THE POINTS GUYOnce you complete your TSA PreCheck or Global Entry interview and receive approval for the program, you'll be assigned a KTN.In both programs, your membership (and KTN) is valid for five years before you'll have to renew and pay the application fee again.The TSA PreCheck application fee is $78 for new members.Global Entry costs $120 for a five-year membership and includes TSA PreCheck access.A handful of credit cards will reimburse the application fee for either program.If you're planning to travel internationally multiple times in the next five years, Global Entry probably offers the best bang for your buck, as it expedites entry into the U.S. after international travel and includes TSA PreCheck benefits.Related: 13 things you need to know about Global EntrySEAN CUDAHY/THE POINTS GUYHow do you add a Known Traveler Number to your travel bookings?Once approved for TSA PreCheck, Global Entry or another Trusted Traveler Program, you'll have to follow one additional step to ensure "TSA PreCheck" designation gets printed on your boarding pass: You have to attach your KTN to your airline profile.You can add it to an individual reservation when filling out your personal information at checkout.The airline may offer a specific line for your Known Traveler Number, as in the Southwest Airlines booking below.SOUTHWEST AIRLINESOn some airlines, you'll enter it in the "secure traveler" information field.How to attach your KTN to all future bookingsIf you have a frequent flyer account, you can also just attach your KTN to your airline profile. Once you do this, it should be automatically applied to every booking you make with that airline, as you include your frequent flyer number on the reservation.What to do if you forgot to add a KTN to your flightIf you already booked a flight and forgot to add your Known Traveler Number to your reservation, don't fret. You should be able to easily pull up your reservation and add your KTN.Go to the airline's website or mobile app. Pull up your reservation using the confirmation number (or record locator) the airline gave you when you booked your trip. Then, go to the traveler information section. There should be a line that says "Known Traveler Number," "KTN" or "Secure Traveler Information." Enter your KTN there.If you've already checked in for your flight and downloaded your mobile boarding pass, you may need to re-download the boarding pass to see "TSA PreCheck" appear. If it doesn't, try going to a kiosk and printing it.Related: What to do if a boarding pass isn't marked TSA PreCheckWhere can you find your Known Traveler Number?There are a few ways to find your KTN.Go to the federal dashboardYou can pull up this page from DHS and log in using the personal information you used to apply for TSA PreCheck, Global Entry or another travel program.Your Membership Number/PASSID (shown below) is your KTN.DHSCheck your Global Entry cardIf you have your physical Global Entry card, check the backside. Your nine-digit "PASSID" is your KTN.The location of a Known Traveler Number on a Global Entry card is circled in blue. SEAN CUDAHY/THE POINTS GUYCopy and paste from your favorite airline profileAnother trick: Check your frequent flyer account for the airline you fly with most. If your membership in one of the Trusted Traveler programs is active and you've used TSA PreCheck before, odds are your KTN is on file with your go-to airline.You can copy it and add it to whatever airline you're flying with next.Bottom lineA Known Traveler Number is a code that gets you into the TSA PreCheck lane. It's how the airline and government recognize a trusted traveler who is a member of TSA PreCheck, Global Entry or other similar programs.Keep your number handy and add it to your airline profile. If you're not a member, consider enrolling in one of these programs that give you a KTN and make your trip through the airport less of a hassle.Related reading:When is the best time to book flights for the cheapest airfare?The best airline credit cardsWhich US airline is best? TPG's 2026 rankingsFlight delayed or canceled? Here's what to doThe best credit cards to reach elite statusWhat are points and miles worth? 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