The smartest travelers measure their bags and review the Southwest Airlines Under Seat Dimensions well before departure day. A personal item that fits within 18.5 x 8.5 x 13.5 inches avoids last-minute repacking and keeps your boarding experience calm. Soft-sided bags work best because they can compress slightly under the seat. Pack your phone, wallet, medication, and travel documents in easy-to-reach pockets. With thoughtful preparation, you can walk onto the plane with confidence and settle into your seat without any delays.
