Your carryon can be no bigger than 24” (L) + 16” (W) + 10” (H). If it's bigger than those dimensions, it will need to be checked. Where can I store my carryon? You must store your carryon in the overhead bin.

Southwest Airlines remains one of the most generous yet structured carriers regarding carry-on baggage in 2026. You are permitted one carry-on bag (24 x 16 x 10 inches) and one personal item (18.5 x 8.5 x 13.5 inches). While Southwest rarely weighs carry-on bags, they are very strict about the physical dimensions and the "two-item" rule. If your bag cannot fit in the overhead bin or if you attempt to board with a third item (like a shopping bag or a large camera case), agents will almost certainly require you to gate-check the item. Because Southwest allows two checked bags for free, they expect passengers to utilize the cargo hold for larger items rather than crowding the cabin. In 2026, gate agents frequently use "sizer" boxes during the boarding process to ensure the 24-inch length limit is respected, as oversized bags can significantly delay their high-efficiency boarding turns.