One of the signature parts of the Southwest Airlines experience has long been the idea that boarding position mattered a lot because of first-come, first-served seating. With that characteristic going away, Southwest says it will "evolve" its boarding process.

Sales for assigned seats are expected to begin in the second half of 2025, and the first flights with the new model will operate in the first half of 2026.

It's the end of Southwest Airlines' open seating era. Customers will be able to get assigned seats and and pay for extra legroom. Here's what to know.