Customers can add EarlyBird Check-In to their reservation up to 36 hours prior to a flight's scheduled departure, when it is available. Upgraded Boarding guarantees an A1-A15 boarding position and, when available, can be added to a reservation up to 30 minutes before a flight's scheduled departure.

The primary difference between Southwest's EarlyBird Check-In and Upgraded Boarding is when they are purchased and what specific boarding position they guarantee. EarlyBird Check-In (starting at $15) is an automated service that checks you in 36 hours before departure—12 hours before the general public. It doesn't guarantee an "A" position, but it significantly improves your chances of getting a better spot in the A or early B groups. Upgraded Boarding ($30–$80), however, is only available within 24 hours of the flight and specifically secures a position in the coveted A1–A15 slots, which are the first to board after pre-boarders. While EarlyBird is a "set it and forget it" option to avoid the 24-hour manual check-in scramble, Upgraded Boarding is a premium last-minute splurge for those who want the absolute first choice of seats and overhead bin space, often used by those who were assigned a poor boarding group late in the process.