1. 1Visit allegiantair.com/checkin or open the Allegiant mobile app.
2. 2Enter your confirmation number and name.
3. 3Verify your seat assignments and bag reservations.
4. 4Pay for any additional bags or seat upgrades if desired.
5. 5Download your mobile boarding pass or print your paper boarding pass.

Government-issued photo ID (such as a driver's license or passport) for passengers over 18. Minors traveling alone may need a birth certificate or other identification with birthdate.

Seats are automatically assigned for free at check-in if not pre-purchased. You can purchase or upgrade seats during online check-in for a fee (typically $0 to $80).

Allegiant Air currently operates exclusively within the continental US and near Canada, so standard domestic check-in rules apply for most flights. A passport is required for non-U.S. citizens.

If checking in multiple passengers under the same confirmation number, you can select which passengers to check in together. Families are not guaranteed seats together unless purchased in advance.

1. 1'Unable to check in online' - You may be required to see an agent at the airport for document verification.
2. 2'Error message on app' - Try clearing browser cache/cookies or using the website instead.
3. 3'Trip no longer shows up' - Ensure you are entering the exact alphanumeric confirmation code without spaces.