Last updated April 2026.
What Is a Known Traveler Number (KTN)?
A Known Traveler Number (KTN) is a 9-digit identification number issued by the Transportation Security Administration (TSA) as part of the Trusted Traveler Programs. This unique identifier is linked to your aviation security profile and is used by airlines and TSA officers to recognize you as a pre-vetted, low-risk traveler. KTNs typically begin with “TT” followed by seven digits, or may consist entirely of digits depending on the program.
When you enroll in a Trusted Traveler Program such as TSA PreCheck, Global Entry, SENTRI, or NEXUS, you receive a KTN that must be added to your airline reservations. This number grants you access to expedited security screening at U.S. airports and, depending on your program, benefits such as TSA PreCheck lanes, expedited customs processing, and trusted traveler status when traveling internationally.
The primary purpose of a KTN is to streamline airport security while maintaining the integrity of aviation safety. By providing your KTN during flight booking, you’re essentially telling the TSA and airlines, “I’ve undergone background vetting and meet security requirements,” which allows you to bypass standard security procedures and enjoy expedited screening.
How to Get a Known Traveler Number
To obtain a KTN, you must first enroll in one of the TSA’s Trusted Traveler Programs. The most popular option is TSA PreCheck, which costs $78 for a 5-year membership. The enrollment process is straightforward and can be completed largely online.
TSA PreCheck Enrollment Steps:
- Visit the official TSA PreCheck enrollment website (tsa.gov/precheck).
- Complete the online application, providing personal information, travel history, and background details.
- Pay the $78 enrollment fee using a credit card.
- Schedule an appointment at an enrollment center near you.
- Attend your appointment, where you’ll provide fingerprints, a government-issued government-issued ID, and proof of citizenship or lawful permanent residency.
- Upon approval, you’ll receive a KTN via email and physical credential card.
The entire process typically takes 2-3 weeks from application to approval. If you travel internationally, you may want to consider Global Entry instead, which includes TSA PreCheck benefits and costs $100 for 5 years.
Other Trusted Traveler Programs offering KTNs include SENTRI (for frequent travel to Mexico) and NEXUS (for frequent travel to Canada). Each program has different costs and eligibility requirements, but all provide a KTN for use on airline reservations.
Where to Find Your KTN
Once you’re approved for a Trusted Traveler Program, you’ll receive your KTN through multiple channels. You’ll typically find it in the following locations:
- Enrollment Confirmation Email: Your KTN is sent immediately after your in-person appointment is completed and your background check clears.
- TSA.gov Account: Log into your trusted traveler account on the TSA website to view your KTN and credential details.
- Physical Credential Card: Your KTN is printed on the official credential card you receive by mail.
- Mobile Apps: Download the official app for your specific program (TSA PreCheck, Global Entry, etc.) to access your KTN digitally.
If you’ve misplaced your KTN, you can retrieve it by logging into your TSA account, calling the Trusted Traveler Program customer service line, or checking your enrollment confirmation email. Keep your KTN in an easily accessible location so you can add it to flight reservations quickly.
TSA PreCheck vs Global Entry vs SENTRI vs NEXUS
| Program | Cost (5 Years) | Validity | Key Benefits | KTN Included? |
|---|---|---|---|---|
| TSA PreCheck | $78 | 5 years | Expedited TSA screening at U.S. airports, keep shoes/belt on, laptop stays in bag | Yes |
| Global Entry | $100 | 5 years | TSA PreCheck + expedited customs/immigration upon U.S. return, kiosks at major airports | Yes |
| SENTRI | $122.50 | 5 years (for U.S. citizens) / varies for others | Expedited border processing at U.S.-Mexico land borders, RFID-enabled card | Yes |
| NEXUS | $120 | 5 years | Expedited border processing at U.S.-Canada border, dedicated lanes | Yes |
Most frequent international travelers find Global Entry to be the best value, as it includes TSA PreCheck benefits plus expedited customs screening. If you primarily travel domestically, TSA PreCheck is sufficient and more affordable. SENTRI and NEXUS are specialized programs for specific border regions.
How to Add Your KTN to Flight Reservations
Adding your KTN to airline reservations is essential to receive TSA PreCheck and other expedited screening benefits. The process varies slightly by airline, but the general steps are:
During Online Booking:
- When booking your flight on an airline website, look for a field labeled “Known Traveler Number,” “Frequent Flyer Information,” or “Special Services.”
- Enter your 9-digit KTN in the appropriate field.
- Complete your reservation normally.
- Confirm that your KTN appears on your confirmation email and airline receipt.
For Existing Reservations:
- Log into your airline account or visit the airline’s website.
- Find your reservation using your booking reference or confirmation number.
- Select “Edit” or “Manage Booking.”
- Add your KTN in the special services section.
- Save your changes and verify the update in your reservation confirmation.
By Phone: Call your airline’s customer service and provide your reservation confirmation number and KTN. Customer service representatives can add it immediately.
It’s important to add your KTN to every flight reservation, even if you’ve added it previously, as some systems don’t retain it automatically. At the airport, your TSA PreCheck eligibility will appear on your boarding pass with a “TSA PreCheck” indicator or badge.
KTN vs Redress Number
While a KTN and a Redress Number serve different purposes, they’re often confused. Understanding the distinction is important for travelers:
Known Traveler Number (KTN): A 9-digit identifier issued to pre-vetted, low-risk travelers enrolled in Trusted Traveler Programs. It grants expedited screening privileges and is added to reservations proactively.
Redress Number: A 13-character identifier issued to travelers who believe they’ve been misidentified at airport security or who are experiencing delays due to a name match. Redress numbers are obtained through the DHS Travel Redress Inquiry Program (TRIP) and are used to prevent future security issues.
In short: A KTN is a reward for being verified as low-risk, while a Redress Number is a corrective measure for travelers experiencing security complications. They serve opposite purposes.
Frequently Asked Questions
Can I Use My KTN on Flights Booked by Someone Else?
No. Your KTN is personal and tied to your identity. When someone else books your ticket, you’ll need to add your KTN after the reservation is created using the “Manage Booking” or “Special Services” section of the airline website or by contacting the airline directly. Alternatively, if you’re booking through a travel agent, provide them with your KTN explicitly so they can add it during the initial booking.
Does My KTN Work on All Airlines?
Yes. Your KTN is recognized by all major U.S. airlines and most international carriers flying to/from the United States. TSA PreCheck screening lanes are available at more than 200 U.S. airports, and Global Entry kiosks are at major international airports. Check the TSA website to confirm programs are available at your departure airport.
What Happens If I Forget to Add My KTN?
If you forget to add your KTN to your reservation, you won’t receive TSA PreCheck benefits for that flight and will go through standard security screening. You can still add your KTN after booking by managing your reservation online or calling the airline. If you realize at the airport, inform the TSA officer at security—they may be able to verify your enrollment status and grant you PreCheck screening, though this isn’t guaranteed.
Do I Need a Biometric Passport to Use My KTN?
Not for domestic flights. For domestic U.S. travel, you only need a valid government-issued ID (driver’s license, passport, military ID, etc.). However, if you have Global Entry or NEXUS, a biometric passport or U.S. passport is required for international travel and border crossings.
Can My Family Members Use My KTN?
No. KTNs are non-transferable. Each family member must enroll in their own Trusted Traveler Program and receive their own KTN. Children as young as 1 year old can enroll in TSA PreCheck, and infant KTNs can be added to flight reservations.
How Long Does a KTN Remain Valid?
A KTN is valid for the duration of your Trusted Traveler Program membership, typically 5 years. When your membership expires, you’ll receive a renewal notice and can renew your enrollment (usually at a reduced cost if done within a grace period). Your KTN will be updated upon renewal, and you’ll need to update any saved airline profiles with your new number.