$49 Cheap Frontier Airlines flights Seattle (SEA) to Ontario (ONT)

Make use of the “Price (lowest to highest)” filter on Expedia to search for cheap Frontier Airlines round-trip flights from $98 from SEA to ONT. Affordable one-way fares from $49 are also available.**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.

January is one of the cheapest months to fly to Ontario with Frontier Airlines. You could also find excellent prices on return and one-way fares in April.

For cheap Frontier Airlines fares from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT), start searching one to three months before your intended departure. Securing domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also affect the overall price. Sunday is generally the cheapest, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking on a Sunday.**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.

Depart on one of Frontier Airlines’s 2 direct weekly flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT). To see your choices, enter your dates, destination and origin and hit search. Then select the “Nonstop” and “Airline” filters.

The travel time for a nonstop Frontier Airlines flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) takes around 2h 37m.

Setting off from SEA at 4:35PM UTC-8, the first Frontier Airlines flight to ONT lands at 7:12PM UTC-8. Flying earlier in the day means you’re less likely to encounter delays.* Don’t like early starts? The last Frontier Airlines flight from SEA to ONT departs at 4:35PM UTC-8 and touches down at 7:12PM UTC-8.*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.

Frontier Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Ontario come in to Los Angeles - Ontario Intl. Airport (ONT), Los Angeles Intl. Airport (LAX) and John Wayne Airport (SNA). The main Ontario gateway serviced by this carrier is ONT. It’s always worth considering flights arriving at other nearby airports on Expedia as you may find cheaper prices.

Travel from SEA to ONT with Frontier Airlines and enjoy a range of benefits starting with a rewarding loyalty program. When booking through Expedia as a Frontier Miles and One Key™ member, you may 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.

Most likely, you’ll travel on an Airbus A320neo for your Frontier Airlines flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT). However, you could end up on an alternative aircraft if operational demands require it.

Depending on your fare type, a fee generally applies if you modify or cancel your booking more than 24 hours after confirmation. To find plane tickets with more flexibility, select our “Changes included” or “No cancel fee” filter when you search for flights. For additional information on changing or canceling your reservation, head to “Trips,” select your flight and click on “Manage Booking.”