what terminal is southwest at sky harbor ? Southwest Airlines operates out of Terminal 4 at Phoenix Sky Harbor International Airport. Terminal 4 is the largest terminal at the airport and serves as the primary hub for several airlines, including Southwest. It offers a wide range of facilities and services to accommodate travelers, including check-in counters, security checkpoints, boarding gates, baggage claim areas, and various dining and retail options. Terminal 4 is conveniently located near the airport's parking facilities and ground transportation options, making it easily accessible for passengers flying with Southwest Airlines. Passengers can look for Southwest signage and staff to guide them to the appropriate check-in and boarding areas within Terminal 4.