Frontier Airlines allows customers to check in for their flights either online, starting 24 hours before departure, or at the airport. The frontier check-in process online requires entering your confirmation number and last name. At the airport, you can use self-service kiosks to print boarding passes and check bags or go to an agent at the ticket counter. Checking in ahead of time online or early at the airport can save time and reduce stress on the day you fly. Need more information on checking in for your Frontier Airlines flight? Help is available. Call 1 (855) 981-4544 or (844) 902-4930 (OTA-Skip Waiting) to assist with the check-in process. You can also read a blog on the Airlinepetpolicy website.