what terminal is Frontier Airlines at SFO refers to the common question travelers ask when departing from San Francisco International Airport (SFO). The answer to what terminal is Frontier Airlines at SFO is that Frontier Airlines operates out of Terminal 2 at San Francisco Airport. Passengers flying with Frontier Airlines will check in, go through security, and board their flights from this terminal. Knowing the correct terminal is important for a smooth travel experience, ensuring that passengers can easily navigate SFO and reach the right gate for their flight.