<p data-start="77" data-end="515">Southwest Airlines operates under a boarding system unlike any other major U.S. carrier&mdash;and that difference makes the check-in process critically important. Instead of assigned seats, Southwest uses boarding positions, which are directly influenced by <em data-start="329" data-end="335">when and <em data-start="340" data-end="345">how you check in. Understanding the 24-hour rule is not optional; it&rsquo;s essential if you want overhead bin space, seat choice flexibility, and a smoother boarding experience.



<p data-start="517" data-end="859">This expert guide breaks A completeSouthwest check-in guide explaining the 24-hour rule, online check-in steps, and how to improve your boarding group, when upgrades make sense, and how to avoid common traveler mistakes. For personalized assistance, Southwest customer support is available at <strong data-start="839" data-end="858">+1-877-593-4887.