Does United Require 24 Hour Check-In?

United Airlines does not require passengers to check in exactly 24 hours before departure, but the airline opens online and mobile check-in 24 hours prior to the scheduled flight time. This allows travelers to select seats, confirm itineraries, pay for baggage, and access digital boarding passes. While 24-hour check-in is optional, it is highly recommended to secure seating preferences and avoid airport delays. As of June 3, 2025, United enforces a stricter minimum check-in deadline: for most domestic flights, check-in and baggage drop must be completed at least 45 minutes before departure, regardless of whether a passenger checks bags or not. Previously, passengers without checked baggage could check in as late as 30 minutes before takeoff. This change aligns United with other major U.S. airlines such as Delta and American. For international flights, the check-in deadline remains 60 minutes before departure, though certain international airports may have even earlier requirements, sometimes up to 75–90 minutes prior. United recommends arriving at the airport two hours early for domestic and three hours early for international flights. If passengers fail to check in by the deadline, the airline may deny boarding, cancel reservations, or prevent baggage check. Although United does not mandate 24-hour check-in, early check-in is essential for efficient airport navigation, timely boarding, and on-time departure. Travelers should utilize the 24-hour online check-in window to reduce time spent at airport counters and avoid issues at security or boarding gates. Check-in can be completed via United’s website, mobile app, or airport kiosks. United’s mobile app also provides real-time updates, gate information, and digital boarding passes. Frequent flyers and MileagePlus members benefit from checking in early by accessing better seat assignments and upgrade opportunities. Passengers traveling with pets, unaccompanied minors, or those needing special assistance may need to check in at the airport and should arrive early. United’s policy aims to standardize check-in procedures and minimize delays caused by last-minute processing. The updated 45-minute rule for domestic flights eliminates confusion about different cutoff times for passengers with or without checked bags. United’s check-in deadlines vary slightly depending on the departure airport, and travelers are urged to verify specific airport requirements before their trip. While 24-hour check-in is not compulsory, using it ensures smoother boarding and access to preferred seating. Passengers can also use this time to confirm travel documents and TSA PreCheck status. Overall, United Airlines encourages all passengers to complete check-in as early as possible, ideally right when the 24-hour window opens, to secure boarding position, avoid gate reassignments, and reduce the risk of denied boarding. In summary, United does not require 24-hour check-in, but the airline sets strict final check-in deadlines (45 minutes domestic, 60 minutes international), making early check-in an important part of a stress-free travel experience. Travelers should always aim to check in exactly at the 24-hour mark or as early as possible within that window to avoid complications and ensure compliance with United’s boarding policies.