If you’re flying with United Airlines, it’s important to know how early you can check in to ensure a smooth and timely departure. United Airlines provides several check-in options designed to fit different travel needs, including online check-in, mobile check-in, airport self-service kiosks, and check-in counters. For most flights, United’s online check-in opens 24 hours before the scheduled departure time and closes 60 minutes before domestic flights and 90 minutes before international flights. You can complete the online check-in process by visiting the official United Airlines website or using the United mobile app. During online check-in, passengers can select or change seats, add baggage, provide passport details (for international travel), and download or print boarding passes. This method is ideal for travelers without checked baggage who want to head straight to the gate after security. If you have checked luggage, you can still check in online and use bag drop services at the airport, which are available until around 45 to 60 minutes before departure. For travelers who prefer checking in at the airport, United Airlines airport counters typically open 3 hours before international flights and 2 hours before domestic flights. It's recommended to arrive at least 2 hours before a domestic flight and 3 hours before an international flight to allow enough time for check-in, baggage drop, security clearance, and potential travel document checks. At most major airports, United also offers self-service kiosks that allow you to check in, print your boarding pass, and print baggage tags. These kiosks are easy to use and help reduce wait times, especially during busy travel periods. For Premier Access, Business Class, and First Class travelers, United provides priority check-in lanes that streamline the process. Passengers with special needs, those traveling with infants, or those flying with pets may be required to check in at the counter for assistance. In certain cases—such as international flights with visa requirements or travel to specific destinations—United may require in-person document verification even if you’ve checked in online. For smooth travel, it’s best to complete online check-in as soon as it becomes available and arrive early at the airport. Doing so helps avoid delays, provides more seating options, and gives time to manage any unexpected changes. United Airlines also sends alerts and reminders through email and the app to let you know when it’s time to check in and if any updates occur with your flight. In conclusion, you can check in for a United Airlines flight 24 hours before departure online, while airport counters open 2 to 3 hours prior depending on the flight type. Whether you’re flying domestically or internationally, early check-in ensures a smoother experience and better control over your travel plans with United Airlines.