What Terminal Does Southwest Use at PHX, Southwest Airlines operates primarily out of Terminal 4 at Phoenix Sky Harbor International Airport (PHX). As one of the busiest airports in the United States, Southwest's choice of Terminal 4 ensures efficient operations and convenient access for passengers. Terminal 4 offers a wide range of amenities, including dining options, retail stores, and comfortable seating areas. With its modern facilities and streamlined design, Terminal 4 provides a seamless travel experience for Southwest passengers departing or arriving at PHX. Whether you're traveling for business or leisure, Southwest's use of Terminal 4 ensures a smooth journey from start to finish.