United Airlines – Online Check-in is available up to 24 hours prior to departure.
Need any of the following to use online check-in – Mileage Plus member with a united.com password, reservation number, credit card number used to purchase the United Airlines tickets.
Available for domestic and international flights.
If you are traveling on more than one airline during the check-in process, you will be alerted if your itinerary permits check-in on other airlines.
Drop off luggage at curbside check-in or with an agent.