I don't appear to be able to browse much more at this time. Try again later, please. However, according to popular information, Southwest Airlines SEA Terminal is based out of Seattle-Tacoma International Airport's (SEA) Concourse C. Both local and some international flights operated by Southwest are served by this terminal. Due to the possibility of gate assignments changing, be careful to check your flight details for any adjustments. Asking the airline or the airport directly is always the best approach to get the most up-to-date information. Tell me if you require any other information!