Does United Require 24-Hour Check-In? A Clear Guide for Travelers

Many passengers wonder, “Does United require 24-hour check-in?” The short answer is no, United Airlines does not require you to check in exactly 24 hours before your flight. However, it’s highly recommended to do so as soon as the check-in window opens, which is typically 24 hours before your scheduled departure time. Early check-in gives you the opportunity to select your preferred seat, pay for checked baggage, and receive your boarding pass in advance, saving valuable time at the airport.

United offers several convenient check-in methods: online, via the United mobile app, self-service airport kiosks, and at the ticket counter. Online and mobile check-in are available starting 24 hours before departure and typically close 60 minutes before the flight departs. Checking in online or through the app allows you to skip long lines, review your travel details, and download a digital boarding pass that can be saved to your phone.

The United Airlines mobile app is especially convenient for travelers who want a smooth, paperless experience. It allows you to check in quickly, change or confirm seats, get real-time flight updates, and access your mobile boarding pass all in one place. You can also link it to your Apple Wallet or Google Wallet for faster access at security and the gate.

If you’re checking bags, it's still important to arrive at the airport early. As of June 3, 2025, United requires all travelers on domestic flights to check in at least 45 minutes before departure, even if you’ve already checked in online. For international flights, the check-in cutoff is 60 minutes before departure. These are strict cutoffs, and failing to meet them could result in denied boarding, even if you’ve completed online check-in.

For travelers who prefer to check in at the airport, United provides self-service kiosks and full-service check-in counters. These options are useful if you’re checking bags, traveling with pets, or need extra assistance. However, keep in mind that airport check-in lines can get long, especially during peak travel times or holidays. Checking in online 24 hours in advance can help you skip those lines and head straight to baggage drop or security.

In conclusion, while United does not require you to check in exactly 24 hours before your flight, it is in your best interest to do so. The 24-hour window is when check-in becomes available—not when it becomes mandatory. The earlier you check in, the more likely you are to get a better seat, avoid delays, and enjoy a more relaxed travel experience. Whether online, via mobile app, or at the airport, United Airlines offers flexible and easy check-in options to help get your trip off to a smooth start.