The move is further evidence of the ongoing consolidation between the two airlines since Southwest acquired AirTran earlier this year.
AirTran flights will depart from gates in Concourse B. Baggage claim will shift to carousel number 6, adjacent to Concourse B on the lower level.
With the airport's no. 1 and the no. 2 airlines operating out of the same facility, BWI has nearly 70 percent of its passengers in roughly the same area. Because of concerns about congestion, the airport has made some changes for pick-up of passengers.
As of the end of October, new pick-up zones have been created for hotel shuttles and off-site parking shuttles. There are a total of four areas where arriving passengers can be picked up.
According to an email sent to customers of PreFlight Parking, which offers service at BWI, off-site parking operators must pick up passengers at the second curb outside baggage claim doors 7-9 or the International Terminal.
Some arriving Southwest passengers have complained that it's a long hike from baggage claim to the pick-up.
A BWI spokesman said the pick-up zones are similar to those for parking and rental car shuttle buses. He said the airport will continue to evaluate the roadway changes.