Does United Require 24-Hour Check-In?

If you’re flying with United Airlines, you might be wondering: Does United require 24-hour check-in? The simple answer is no, United Airlines does not require passengers to check in exactly 24 hours before their flight. However, the airline opens its check-in window 24 hours before departure, which is when passengers are encouraged to check in online or through the United app. While checking in at the 24-hour mark is not mandatory, it is highly recommended to ensure a smoother travel experience and to meet United's official check-in deadlines.

United allows you to check in online, via the United mobile app, or at a kiosk or check-in counter at the airport. The check-in window opens exactly 24 hours before your scheduled flight departure time and closes 45 minutes before departure for domestic flights and 60 minutes before departure for international flights. Failing to check in before these cutoffs may result in denied boarding or cancellation of your seat. So while 24-hour check-in isn't a rule, meeting the minimum check-in deadline is required to board your flight.

Checking in as soon as the 24-hour window opens has its advantages. Early check-in gives passengers the chance to select better seats, add baggage, confirm TSA PreCheck, and receive timely updates about flight status, gate changes, or delays. Frequent flyers and travel experts often suggest checking in exactly at the 24-hour mark to increase the chances of seat upgrades and better in-flight services. This is especially useful for basic economy ticket holders who want to make the most of their options.

If you’re traveling without checked luggage, checking in through the United app or online and using a mobile boarding pass means you can skip the check-in counter and head straight to security. However, if you have bags to check or need to update documents, you’ll still need to be at the airport early enough to complete those steps within the check-in window. United advises passengers to arrive 2 hours early for domestic flights and 3 hours early for international flights, regardless of when you check in.

To summarize, United Airlines does not require 24-hour check-in, but checking in during that window is strongly advised. You must check in at least 45 minutes before domestic flights and 60 minutes before international flights, or you risk missing your flight. For the best travel experience, use the United mobile app or website to check in as early as possible. This helps avoid delays, gives you access to better options, and ensures that you’re ready to fly without stress. Whether you’re a first-time traveler or a frequent flyer, understanding United's check-in policies can help you travel with confidence.