Do you know Which Terminal is Southwest Airlines at SFO? says the airline operates from Terminal 1. The terminal is easy to find and has friendly staff. The check-in process was quick and simple, making it stress-free for travelers. While waiting for their flight, the customer enjoyed browsing the many shops and restaurants in the terminal. Security lines moved fast, adding to a pleasant experience. Overall, the review suggests that if you are flying with Southwest, heading to Terminal 1 will make for a great travel experience!