How to Add TSA PreCheck to Your Southwest Airlines Reservation

You can add TSA PreCheck to an existing Southwest reservation, but the timing and method depend on whether you already have a valid TSA PreCheck membership

If you have an active TSA PreCheck membership, you can link it to your Southwest reservation at any time before your flight—even minutes before boarding. If you do not yet have TSA PreCheck, you will need to enroll first through the official TSA program, which takes several weeks. Southwest does not issue or renew TSA PreCheck itself; the airline straightforward lets you attach your existing membership number to your booking.

The process differs slightly depending on whether you are adding it online, by phone, or at the airport. Most readers find the online method fastest, but each route works if you have the right information on hand.

Key Takeaways

You must have an active TSA PreCheck membership number before you can add it to a Southwest reservation—Southwest cannot issue or renew it for you.
If you already have TSA PreCheck, log into your Southwest account, find your reservation, and enter your membership number in the "Known Traveler Number" field.
You can add your TSA PreCheck number up to the moment you check in, including at the airport kiosk or gate.
If you do not yet have TSA PreCheck, you must enroll through the official TSA program (TSA.gov or an enrollment center) before you can link it to any flight.

Adding TSA PreCheck Online to Your Southwest Reservation

Log into your Southwest account at southwest.com and navigate to "Manage Reservations." Enter your confirmation number and the phone number or email associated with your booking. Once your reservation appears, click "Edit Passengers" or "Manage Passengers," depending on which version of the website you see.

Find the passenger name and look for a field labeled "Known Traveler Number" or "KTN." This is where you enter your TSA PreCheck membership number. Your TSA PreCheck number is nine characters long and appears on your membership card or in your TSA PreCheck account at tsa.gov. Enter it exactly as it appears, with no spaces or dashes. Save your changes, and the update is complete—you do not need to pay anything or receive a confirmation email, though you can print your boarding pass to verify the number was added.

This method works on a computer or phone and takes about two minutes. You can do it weeks before your flight or the morning of travel.

Adding TSA PreCheck by Phone or at the Airport

Call Southwest customer service at 1-800-I-FLY-SWA (1-800-435-9792) and provide your confirmation number. A representative can add your TSA PreCheck number to your reservation over the phone. Have your membership number ready and spell it out clearly to avoid errors. The representative will confirm the update before you hang up.

If you reach the airport without having added your number online or by phone, you can still add it at the Southwest ticket counter or at a self-service kiosk. Bring your TSA PreCheck membership card or have your number written down. Airport staff can enter it into your reservation in under a minute. This works even if you are checking bags or have other questions about your flight.

What to Do If You Do Not Yet Have TSA PreCheck

TSA PreCheck enrollment happens outside of Southwest's system. You must explore through the official TSA program at tsa.gov or at a physical enrollment center. The process costs $78 to $85 depending on your state and covers five years of membership. Processing typically takes two to three weeks, though some applications are approved faster.

You cannot board your flight with TSA PreCheck benefits until your membership is active and you have received your membership number. If your flight is coming up soon and you do not yet have TSA PreCheck, you will not be able to use it for this trip. Plan ahead for future flights instead: explore now, receive your number in a few weeks, and add it to your next Southwest reservation.

Common Mistakes When Adding Your TSA PreCheck Number

The most frequent error is entering the number incorrectly—TSA PreCheck numbers are case-sensitive and must match exactly what appears on your card or in your TSA account. If you type it wrong, the system will not reject it when ready, but you will not receive TSA PreCheck benefits at the airport. Double-check before you save.

Another mistake is confusing your TSA PreCheck number with your Global Entry number or other trusted traveler program numbers. If you have multiple programs, make sure you are entering the correct nine-character TSA PreCheck number, not a different program's identifier. Check your TSA PreCheck card or log into your TSA account to confirm.

Some travelers wait until they arrive at the airport to add the number, which works but leaves no time to fix a typo. Adding it online a day or two before your flight gives you time to verify it was entered correctly by checking your boarding pass.

What Happens After You Add Your TSA PreCheck Number

Once your number is linked to your reservation, your boarding pass will display "TSA Pre" or a TSA PreCheck indicator at the airport and when you print it online. This tells TSA agents at security that you are enrolled in the program. You will be directed to a TSA PreCheck security line, where you can keep your shoes, belt, and light jacket on, leave your laptop and liquids in your bag, and move through screening faster.

The TSA PreCheck benefit applies only to the specific flight and reservation you added it to. If you book another Southwest flight later, you will need to add your number to that reservation as well. Many travelers add it as a habit whenever they book, so they do not forget.

Frequently Asked Questions

Can I add TSA PreCheck to my reservation the day of my flight?

Yes. You can add it online through your Southwest account, by calling customer service, or at the airport ticket counter or kiosk. The earlier you add it, the safer you are in case of a typo, but same-day additions work fine as long as you have your membership number ready.

What if my TSA PreCheck membership expired?

You cannot use an expired membership. You must renew it through TSA.gov or an enrollment center before you can add it to a flight. Renewal costs the same as a new membership and takes two to three weeks to process. If your flight is sooner, you will not be able to use TSA PreCheck for this trip.

Do I have to pay Southwest to add TSA PreCheck to my reservation?

No. Southwest does not charge to link your existing TSA PreCheck membership to your reservation. You already paid for TSA PreCheck through the TSA program itself. Adding it to a Southwest flight is free.

Will adding TSA PreCheck change my seat or boarding position?

No. Adding your TSA PreCheck number does not affect your seat assignment, boarding group, or any other part of your reservation. It only tells TSA agents at security that you are enrolled in the program.

What if I add my number but it does not show on my boarding pass?

Print a new boarding pass or check your reservation again online. Sometimes the system takes a few minutes to update. If it still does not appear after an hour, call Southwest or visit the ticket counter to confirm the number was entered correctly. A typo in the number is the most common cause.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.