Quite a few SW flights share flight numbers - in other words, they consider the same flight to have originated in one city, stopped in one or two others, and concluded at the last city. If you're a passenger ticketed on two or more legs with the same flight number, can you remain on board and choose a new seat (or stay in the same one) between flights, or is everyone "de-boarded" and you have to re-board with the new A, B, C groups?

You MUST stay on board as they come through and count you.

Once they count you, you can pick a new seat. I think you can then get off but not sure how to 'save' the seat you may have re-selected.

As tmh said, you have to remain on board until they take a head count. After that, you can move to a new seat. The FAs almost always make an announcement when they've finished the head count. I've been flying SW over 20 years and I've never been on a multi-segmented flight where they allow you to deplane during the stop over. Their schedules are so tight (usually 15-20 min) that there's not enough time for you to do that.

Yes, you can move to another seat if you continue your flight. You are not allowed to leave the plane.

Thanks dfr4848 and FainaAgain. My trips have always been single point to point and wasn't aware they didn't let you off. Makes sense when you consider their turnaround time.