UNITED check-in time varies depending on the check-in method. So before you know what time to check in, see how to check in.

1. 
   Online check-in - If the customer is traveling with UNITED, he can check-in with UNITED online. Online check-in starts 24 hours before departure. See how to check in online.

First, access the official UNITED account.
Then click on the Trip Organize button.
Then write your ticket number and last name.
Then click on the button to continue.

Your booking information page will open and you will click on the option to check in from that page.

The boarding pass will then be sent to your email address. Print it out.

2. 
   At the Airport – You can check in after you arrive at the airport. Check-in time at the airport is 2-3 hours before departure. You go to the check-in counter at the airport and then present your ticket. The UNITED counter staff will give you a boarding pass.
3. 
   Mobile app - Customers can check-in to UNITED with the mobile app. Here's how to do it:-

First download the UNITED Mobile app.
Then fill in your ticket number and last name and submit.
Click on the link to check in from your reservation information page.
Your boarding pass will then live on your phone Let's print it out.
The airline staff will check it when you go to the plane.