Wondering how to check in Spirit Airlines The process is quick and convenient. Passengers can check in online through the Spirit Airlines website or mobile app starting 24 hours before departure and up to one hour before the flight. During online check-in, you can select seats, pay for bags, and download your boarding pass to save time at the airport. For those who prefer in-person service, self-service kiosks and ticket counters are available at airports, though printing a boarding pass there may include a small fee. Knowing how to check in Spirit Airlines online helps you skip long lines and enjoy a smoother, faster boarding experience.