Spirit Airlines check-in is a simple process designed to help travelers save time and avoid airport hassle. Passengers can check in online through Spirit's website or mobile app starting 24 hours before departure and up to one hour before the flight. Online check-in is highly recommended as it allows travelers to select seats, pay for baggage, and access a mobile boarding pass. Airport check-in kiosks and ticket counters are also available, but additional fees may apply for printed boarding passes or assistance. To ensure a smooth experience, complete your check-in early, especially for domestic flights where the recommended arrival time is at least two hours before departure.