# How to Add TSA PreCheck to an Existing United Reservation? How to Add TSA PreCheck to an **+1-844-570-3589** Existing United Reservation easily update booking online add Known Traveler Number confirm boarding pass and enjoy faster airport security screening Traveling through airport security can be time consuming, especially during busy travel periods. TSA PreCheck is a program that allows eligible travelers to move through security faster by using dedicated lanes and avoiding common screening steps. If you already booked a United Airlines flight and forgot to add your TSA PreCheck number, do not worry. United allows passengers to add it to an existing reservation with ease. This guide explains how to add TSA PreCheck to an existing United reservation, why it matters, and how to make sure it works correctly before your flight. ## What Is TSA PreCheck TSA PreCheck is a trusted traveler program that offers expedited airport security screening. Approved travelers usually do not need to remove shoes belts or light jackets and can keep laptops and liquids in their bags. Once approved you receive a Known Traveler Number which must be added to your airline reservation to receive TSA PreCheck benefits. ## Why TSA PreCheck Must Be Added to Your Reservation Having TSA PreCheck approval alone is not enough. Your Known Traveler Number must be attached to your United Airlines reservation. If it is missing you will not see the TSA PreCheck indicator on your boarding pass and will need to go through standard security screening. Adding TSA PreCheck to your booking ensures that your eligibility is recognized by the airline and airport security systems. ## When You Can Add TSA PreCheck to a United Booking You can add TSA PreCheck to your United reservation at almost any time before check in. It can be added immediately after booking or even shortly before your flight. However it is best to add it as early as possible to avoid last minute issues or system delays. ## How to Add TSA PreCheck Through the United Website One of the easiest ways to add TSA PreCheck to an existing United reservation is through the official United website. First go to the United website and click on the My Trips section. Enter your confirmation number and last name to access your booking. Once inside your reservation look for passenger details or secure traveler information. Enter your Known Traveler Number exactly as provided and save the changes. After saving review your details carefully to ensure the number is entered correctly. ## Adding TSA PreCheck Using the United Mobile App United Airlines also allows travelers to add TSA PreCheck through its mobile app. Open the United app and log in to your account. Access your upcoming trip and tap on traveler information or passenger details. Enter your Known Traveler Number in the TSA PreCheck field and save the update. The app usually syncs changes quickly making it a convenient option for travelers on the go. ## Adding TSA PreCheck During Online Check In If you did not add TSA PreCheck earlier you may still be able to add it during online check in. When checking in online you will be asked to confirm passenger information. Look for a field labeled Known Traveler Number and enter your number before completing check in. Once check in is complete review your boarding pass to confirm that TSA PreCheck appears. ## Contacting United Customer Support If you are unable to add TSA PreCheck online you can contact United customer support for assistance. Provide the agent with your booking reference and Known Traveler Number. The agent can manually add the number to your reservation and confirm that it has been applied correctly. This option is useful if your booking has special conditions or was made through a third party. ## Adding TSA PreCheck at the Airport In some cases United staff at the airport may be able to add TSA PreCheck to your reservation before check in. Visit a United check in counter and present your identification and Known Traveler Number. While airport assistance is possible it is not guaranteed especially during peak travel times. It is always better to add TSA PreCheck before arriving at the airport. ## How to Know If TSA PreCheck Was Added Successfully After adding your Known Traveler Number check your boarding pass once it is issued. Look for the TSA PreCheck indicator printed on the boarding pass. If the indicator is present you can use the TSA PreCheck security lane at participating airports. If it does not appear double check your traveler information and confirm that your name and date of birth match your TSA PreCheck enrollment exactly. ## Common Reasons TSA PreCheck Does Not Appear There are several reasons why TSA PreCheck may not show on your boarding pass. Your Known Traveler Number was entered incorrectly The name on your reservation does not match your TSA PreCheck profile Your TSA PreCheck membership has expired The airport does not support TSA PreCheck Correcting these issues early can help ensure smooth security screening. ## Name Matching Is Very Important The name on your United reservation must match exactly with the name used for TSA PreCheck enrollment. Even small differences such as missing middle names or spelling variations can prevent TSA PreCheck from applying. If there is a mismatch contact United Airlines to correct the passenger name before adding TSA PreCheck. ## Special Situations and Connecting Flights If your itinerary includes multiple flights operated by United or partner airlines TSA PreCheck should apply to all eligible segments as long as the Known Traveler Number is added correctly. However TSA PreCheck is not guaranteed on every flight and may not appear on all boarding passes due to security requirements. ## Latam Airlines and TSA PreCheck Connections Some travelers connect between United and Latam Airlines on international itineraries. TSA PreCheck benefits generally apply only to eligible United operated flights departing from participating airports within the United States. If your journey includes different airlines TSA PreCheck availability may vary by segment. ## Traveling With Family Members Children under a certain age traveling with a TSA PreCheck eligible adult may be able to use the expedited lane even if they are not enrolled. However teenagers and adults must have their own Known Traveler Number added to the reservation. Make sure each eligible passenger has their own TSA PreCheck information entered correctly. ## Tips for a Smooth TSA PreCheck Experience Add your Known Traveler Number immediately after booking Double check spelling and name order Confirm TSA PreCheck appears on your boarding pass Arrive early even with expedited screening Keep your identification ready at security These steps help avoid delays and ensure you enjoy the benefits of TSA PreCheck. ## What to Do If TSA PreCheck Is Missing on Travel Day If TSA PreCheck does not appear on your boarding pass on the day of travel speak with a United agent at the airport. In some cases they may be able to reissue your boarding pass after verifying your Known Traveler Number. If not you will need to go through standard security screening for that flight. ## Benefits of Adding TSA PreCheck to United Flights Adding TSA PreCheck to your United reservation saves time and reduces stress. Travelers often experience shorter lines faster screening and a more comfortable airport experience. For frequent flyers or those traveling during busy seasons TSA PreCheck can make a significant difference. ## Conclusion Adding TSA PreCheck to an existing United reservation is a simple process that can greatly improve your airport experience. Whether you update your booking online through the United website mobile app or customer support the key is ensuring your Known Traveler Number is entered correctly and early. By taking a few minutes to review your reservation and confirm TSA PreCheck status you can enjoy faster security screening and start your journey with confidence. Proper preparation ensures your travel with United Airlines is smooth efficient and stress free from the moment you arrive at the airport.