$78 Cheap Frontier Airlines flights San Antonio (SAT) to Ontario (ONT)

You'll find affordable round-trip Frontier Airlines flights from $165 from SAT to ONT by sorting your results from "Price (lowest to highest)" on Expedia. Or look for options from $78 for a one-way journey.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

Look for cheap Frontier Airlines flights from San Antonio Intl. Airport (SAT) to Los Angeles - Ontario Intl. Airport (ONT) one to three months before your day of departure. Travelers who book domestic flights 34 to 86 days in advance can save 25% compared to those who book just 6 to 12 days ahead. No matter the fare class and itinerary, the best day to book a domestic flight is generally Sunday and the most expensive day is typically Monday. Passengers who book on a Sunday can save 6% on average compared to those who book on a Monday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.

To find the earliest departures from SAT to ONT with Frontier Airlines, filter your search by "Early Morning" and "Morning." Booking an early flight usually means cancellations are less likely.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.

Journey from SAT to ONT with Frontier Airlines and you'll enjoy a host of benefits starting with a rewarding loyalty program. When you book through Expedia as a Frontier Miles and One Key™ member, you may also earn OneKeyCash™* to redeem on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.