Southwest Airlines will begin assigning seats to passengers on its flights starting on Jan. 27, the carrier said Monday, with some customers allowed to choose their seats at booking.

From its start, Southwest has allowed travelers to pick their seats upon boarding the aircraft in a first-come, first-served model. But Southwest customers flying on Jan. 27 or later will either have their seats assigned on checking in at the gate, or will pick their seats when they book the flight.

People paying the basic fare will have a standard seat assigned to them when they check in. Passengers paying the higher “choice” level fare will pick a standard seat when they book a flight. People paying for “choice preferred” fare will also be able to pick “preferred” seats, and the top-tier “choice extra” passengers will be allowed to pick seats with extra legroom.

The lower three tiers can also pay for an upgrade to extra legroom seating, Southwest said.

For the boarding process, customers in all four fare tiers will have to pay for early priority boarding, which will be available starting 24 hours before departure.

After that, the extra-legroom customers will board in the first two groups, along with highest-tier Southwest rewards members and lower-tier rewards members who upgraded to an extra legroom seat.

Currently, Southwest is only allowing customers to book flights leaving Jan. 26 or earlier, with the previous seating model still in effect. Flights with assigned seating will become available for booking starting on July 29.

Southwest said boarding groups three through five are reserved for those with “preferred” level seats and remaining lower-tier rewards members, while groups six through eight will consist of people paying basic and choice-level fares. Flyers with a Southwest credit card will board in group five unless their seat type, fare type or rewards tier dictates otherwise.

Assigned seating is not the only change Southwest has made. The company also ended its longtime free bags policy. 

Now, people paying for “choice extra” fares and members of the higher Southwest rewards tier will get two free checked bags as before, while members of the lower rewards tier and Southwest credit cardholders will get one bag checked for free.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.