If you're wondering what terminal is Frontier Airlines at PHX » , Frontier Airlines operates out of Terminal 3 at Phoenix Sky Harbor International Airport (PHX). This terminal is well-equipped with all the necessary services and amenities, including check-in counters, security checkpoints, and baggage claim areas, ensuring a smooth and convenient travel experience for passengers flying with Frontier Airlines. So, the answer to what terminal is Frontier Airlines at PHX is Terminal 3, where you'll find everything you need for your journey.