Triplohub

It is actually a paid add-on service that Southwest Airlines offers to passengers while they book a flight ticket to enhance their check-in experience. The standard check-in opens 24 hours before the flight, while the Southwest Airlines Early Bird Check In service automatically checks passengers 36 hours before their flight is ready to depart. The airline charges between $15 and $25 per person. In case you miss out on including this add-on service on your reservations, the airline allows you to buy it later anytime before flight departure.