On Southwest Airlines, EarlyBird Check-In is a paid add-on (typically costing $15–$25 per one-way flight in 2026) that automatically checks you in for your flight 36 hours before departure. This is 12 hours earlier than the standard 24-hour check-in window available to the general public. Since Southwest does not have assigned seating, your boarding position (A, B, or C group) is determined by how early you check in. By using EarlyBird, you significantly increase your chances of getting an "A" boarding group, which allows you to board the plane sooner and have a better selection of seats and overhead bin space. However, EarlyBird does not guarantee an "A" position, as passengers with elite status or "Business Select" fares still board first. It is an "auto-check-in" service designed for convenience, so you don't have to worry about manually checking in exactly 24 hours before your flight while you are busy traveling or working.