How Much Are Return Flights to San Francisco International? Return flights to San Francisco International Airport can vary in price depending on factors such as the time of booking, airline, and travel dates. Generally, you can find competitive fares starting from as low as for round-trip flights. Be sure to compare prices and book early to snag the best deals. Visit Us: https://www.flightforus.co.uk/destination/cheap-flights-to-san-francisco