Cheap Frontier Airlines flights Ontario (ONT) to Boston (BOS)

Grab affordable round-trip Frontier Airlines flights from $240 from ONT to BOS by filtering your results from "Price (lowest to highest)" on Expedia. Or look for options for a one-way trip.**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.

Search for cheap Frontier Airlines flights from Los Angeles - Ontario Intl. Airport (ONT) to Logan Intl. Airport (BOS) one to three months before your departure day. 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 type and itinerary, the best day of the week to book a domestic flight is usually Sunday and the most expensive day tends to be 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.

Filter your results by "Early Morning" and "Morning" to see the earliest flights from ONT to BOS. Taking off early means you're less likely to experience cancellations.**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.

Fly from ONT to BOS with Frontier Airlines and you can look forward to a range of benefits starting with a rewarding loyalty program. When booking through Expedia as a Frontier Miles and One Key™ member, you could also earn OneKeyCash™* to use on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.