You can perform the check-in process in several ways but the most preferred and recommended way is Frontier online check-in and Mobile check-in. When you are initiating the check-in process online, you must purchase the bags in advance, as bags necessitate an extended fee at the airport counter. For frontier airlines check in, the passenger needs to visit the official website https://www.flyfrontier.com, the check-in tab will be enabled one day before the departure date. Passenger can complete the check-in process until one hour before departure. On Frontier online check-in page, you can view your itinerary, purchase bags, choose your fancied seats, etc. You can print your boarding pass, but in many airports, the email boarding is permitted. When you finish the check-in process online, you are securing a smile. If you are willing to add more luggage to your cart, do it at the time of online check-in, as the baggage purchased at the airport counter costs you more.