Does United Require 24-Hour Check-In?

United Airlines does not require passengers to check in exactly 24 hours before their flight, but it allows check-in starting 24 hours before departure. This means that travelers flying with United can check in online, through the United mobile app, at a self-service kiosk, or at the airport counter beginning 24 hours before their scheduled flight. However, while checking in at the 24-hour mark is optional, United does have required check-in deadlines that you must follow in order to board your flight without issues.

For domestic flights, passengers must check in and have their bags checked at least 45 minutes before departure. For international flights, the check-in cutoff is 60 minutes before departure. If you miss these cutoff times, you may be denied boarding, even if you have a confirmed ticket. That’s why many travel experts recommend checking in as close to the 24-hour window as possible. This gives you more time to make changes to your seat, avoid last-minute issues, and ensure your boarding pass is ready when you get to the airport.

Checking in 24 hours before your United flight can also improve your travel experience. Early check-in increases your chances of choosing better seat assignments, accessing upgrade options, or correcting any errors with your booking. Many passengers also check in early to add baggage, confirm TSA PreCheck status, or receive alerts about gate changes or delays. The United app makes this process even easier by sending reminders when the 24-hour window opens.

If you’re not checking a bag and already have your boarding pass on your phone, you can head straight to security. But remember, even carry-on-only passengers must check in at least 45 minutes before domestic flights. United enforces this rule strictly to ensure on-time departures. If you’re traveling internationally, you’ll need to go through additional document checks, so arriving at the airport 3 hours before your flight is still recommended, even if you checked in online.

In summary, United does not make 24-hour check-in mandatory, but you are highly encouraged to check in as soon as that window opens. It’s the best way to avoid missing the airline’s final check-in deadlines (45 minutes for domestic, 60 minutes for international) and ensure a smooth airport experience. Whether you’re using the United app, a web browser, or a kiosk at the airport, being prepared and checking in early can save time, reduce stress, and help your trip start off on the right foot.