Yes, you can add TSA PreCheck to your reservation after booking, but the process depends on which airline you used and when you want to travel.

If you already have a valid TSA PreCheck membership number, you can enter it into most airline reservations through their website or by calling their customer service line. The airline will then link your PreCheck status to your booking so the system recognizes you at the airport. This works for flights you booked weeks ago or flights departing soon.

If you do not yet have TSA PreCheck, you will need to enroll first — that process takes time and costs money. You cannot add a membership number you do not have, and you cannot retroactively explore PreCheck benefits to a flight that has already departed.

Key Takeaways

  • You can add your existing TSA PreCheck number to a booked flight through the airline's website, mobile app, or by calling their reservations line.
  • The airline must receive your PreCheck number before you check in; adding it the day of travel usually works, but earlier is safer.
  • If you do not have PreCheck yet, you must enroll through the TSA's official enrollment centers or an approved process provider before you can add it to any flight.
  • Some airlines let you add PreCheck during online check-in; others require you to update your reservation in advance.

How to add PreCheck to a flight you already booked

Log into your airline account on their website or app and find your reservation. Look for a section labeled "Manage Booking," "Trip Details," "Passenger Information," or similar — the exact name varies by airline. Within that section, you should see a field for "Known Traveler Number" or "KTN." Enter your nine-digit TSA PreCheck number there and save the changes.

If you cannot find the field online, call the airline's reservations line with your confirmation number and ask them to add your PreCheck number to the booking. They can do this over the phone in a few minutes. American, Delta, United, Southwest, and most other major carriers accept PreCheck numbers this way.

Once the airline has your number in the system, it will show up on your boarding pass when you check in. You do not need to do anything else — the airport will see the PreCheck indicator and direct you to the PreCheck lane at security.

When you need to add it before check-in

The safest window is 24 hours before your flight, which is when most airlines open online check-in. If you add your PreCheck number during online check-in, it will appear on your mobile boarding pass or printed pass when ready. Many readers report success adding it even a few hours before departure.

Adding it the day of travel is riskier because the airline's system may not sync with TSA's database in time, and airport staff may not see the PreCheck indicator on your boarding pass. If you are flying within the next few days, add your number now rather than waiting until check-in day.

What to do if you do not have PreCheck yet

TSA PreCheck enrollment takes four to six weeks from the time you submit your process. You will need to visit an enrollment center in person for a brief appointment where TSA verifies your identity and takes your fingerprints. The membership costs $78 to $85 depending on the provider and is valid for five years.

You can find enrollment centers through the TSA's official website at tsa.gov/precheck. Search by zip code to see which centers are near you and book an appointment. Some pharmacies, travel agencies, and passport acceptance facilities also offer TSA PreCheck enrollment.

If your flight is within the next month, you will not have time to enroll before that trip. You can still enroll for future travel, but you cannot add PreCheck to a flight that departs before your membership is active.

Differences by airline

Most major carriers — American, Delta, United, Southwest, Alaska, JetBlue, and others — let you add a PreCheck number online through their website or app. Some regional airlines and budget carriers have different systems, so if you do not see a Known Traveler Number field, call the airline directly.

A few airlines, including some international carriers, do not display a PreCheck field in their reservation system at all. In those cases, you can still use your PreCheck membership at the airport — TSA will see your number in their database when you show your ID at security — but the airline's boarding pass will not display the PreCheck indicator. You will still get the PreCheck lane as long as your membership is current.

What happens if you forget to add it before your flight

If you arrive at the airport without having added your PreCheck number to your reservation, you can still use PreCheck at security. Show your ID and boarding pass to the TSA officer at the checkpoint. They can look up your PreCheck membership in their system using your name and date of birth, even if the airline's boarding pass does not show the PreCheck indicator.

You may have a slightly longer wait if the officer has to manually verify your membership, but you will not lose your PreCheck benefit. After this flight, add your number to future reservations so the process is faster and smoother.

Common reasons PreCheck does not show on your boarding pass

You entered the wrong number. Double-check that your Known Traveler Number is exactly nine digits and matches the number on your TSA PreCheck card or enrollment confirmation. Even one wrong digit will cause the system to reject it.

Your PreCheck membership has expired. TSA PreCheck is valid for five years from your enrollment date. If your membership expired, you will need to renew it before the number works again. Check your TSA PreCheck card or log into your account at tsa.gov to see your expiration date.

You added the number to the wrong reservation. If you have multiple bookings, make sure you added your PreCheck number to the correct flight. Some airline systems let you search by date or confirmation number to find the right one.

The airline's system has not synced with TSA's database yet. This is rare but can happen if you add your number very close to departure. Adding it at least a few hours before check-in gives the systems time to communicate.

Frequently Asked Questions

Can I add PreCheck to a flight that leaves tomorrow?

Yes. Add your PreCheck number to your reservation right now through the airline's website or by calling them. The airline should have your number in their system within a few hours, and it will show on your boarding pass when you check in tomorrow. If you are checking in at the airport rather than online, tell the agent you have PreCheck so they can make sure it prints on your pass.

What if the airline says my PreCheck number is invalid?

Check that you entered exactly nine digits with no spaces or dashes. Verify the number against your TSA PreCheck card or your enrollment confirmation email. If the number is correct and the airline still rejects it, your membership may have expired — check tsa.gov or your card for the expiration date. If it is expired, you will need to renew before the number works.

Do I have to add PreCheck to every flight I book?

Yes, you need to add your PreCheck number to each individual reservation. The airline does not automatically link it across all your bookings. Once you add it to a specific flight, it stays with that reservation, but you will need to repeat the process for your next trip.

Can I use PreCheck if I forgot to add my number before I got to the airport?

Yes. Show your ID and boarding pass to the TSA officer at security. They can look up your PreCheck membership in their system using your name and date of birth, and you will be directed to the PreCheck lane. You will not lose your benefit, but adding your number in advance makes the process faster.

What is the difference between adding PreCheck and having Global Entry?

Global Entry is a separate program that includes TSA PreCheck benefits plus expedited customs screening when you return to the United States. If you have Global Entry, you can add that membership number to your airline reservation instead of a PreCheck number — the process is the same, and you will get PreCheck lanes at domestic security checkpoints.