Southwest Airlines operates from Terminal 1 at San Francisco International Airport (SFO). If you're flying with Southwest, head to Terminal 1 for check-in, security, and boarding. Travelers often ask, what terminal is Southwest Airlines at SFO, and the answer is always Terminal 1 for all Southwest departures and arrivals. https://airlinesairportsterminals.com/southwest-airlines/sfo-terminal-san-francisco-airport/