What Terminal is Southwest Airlines at SEA? Southwest Airlines SEA Terminal passengers should expect a streamlined baggage procedure that aligns with the airline's well-known customer-first culture. The B Concourse at SEA, where Southwest mostly operates, has self-service kiosks, dedicated check-in desks, and an efficient luggage drop system to expedite the check-in process. A popular choice for travelers with bags, Southwest Carriers stands out among the major U.S. carriers by offering two free checked bags per ticketed passenger.
