$84 Cheap Flights from Seattle (SEA) to Ontario (ONT)

View $84 flight on Wed, Aug 6, 2025Opens in a new window

Popular airlines from Seattle-Tacoma International Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)

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Cheap Flights from Seattle to Ontario (SEA-ONT)

Prices were available within the past 7 days and start at $84 for one-way flights and $118 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Wed, Jul 30 - Tue, Aug 12
SEA
Seattle
ONT
Ontario
$118 Roundtrip, found 3 days ago
$118
Roundtrip
found 3 days ago
Select Frontier Airlines flight, departing Wed, Jul 30 from Seattle to Ontario, returning Tue, Aug 12, priced at $118 found 3 days ago
Frontier Airlines
Wed, Jul 30 - Tue, Aug 12
SEA
Seattle
ONT
Ontario
$133 Roundtrip, found 3 days ago
$133
Roundtrip
found 3 days ago
Select Frontier Airlines flight, departing Wed, Jul 30 from Seattle to Ontario, returning Tue, Aug 12, priced at $133 found 3 days ago
Frontier Airlines
Tue, Aug 26 - Tue, Sep 2
SEA
Seattle
ONT
Ontario
$149 Roundtrip, found 1 hour ago
$149
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Tue, Aug 26 from Seattle to Ontario, returning Tue, Sep 2, priced at $149 found 1 hour ago
Frontier Airlines
Thu, Aug 14 - Sat, Aug 16
SEA
Seattle
ONT
Ontario
$154 Roundtrip, just found
$154
Roundtrip
just found
Select Frontier Airlines flight, departing Thu, Aug 14 from Seattle to Ontario, returning Sat, Aug 16, priced at $154 just found
Frontier Airlines
Fri, Aug 15 - Sun, Aug 17
SEA
Seattle
ONT
Ontario
$156 Roundtrip, just found
$156
Roundtrip
just found
Select Frontier Airlines flight, departing Fri, Aug 15 from Seattle to Ontario, returning Sun, Aug 17, priced at $156 just found
Hawaiian Airlines
Tue, Aug 12 - Wed, Sep 3
SEA
Seattle
ONT
Ontario
$157 Roundtrip, found 2 days ago
$157
Roundtrip
found 2 days ago
Select Hawaiian Airlines flight, departing Tue, Aug 12 from Seattle to Ontario, returning Wed, Sep 3, priced at $157 found 2 days ago
Delta
Wed, Sep 17 - Tue, Sep 23
SEA
Seattle
ONT
Ontario
$157 Roundtrip, just found
$157
Roundtrip
just found
Select Delta flight, departing Wed, Sep 17 from Seattle to Ontario, returning Tue, Sep 23, priced at $157 just found
Frontier Airlines
Fri, Aug 22 - Tue, Aug 26
SEA
Seattle
ONT
Ontario
$159 Roundtrip, just found
$159
Roundtrip
just found
Select Frontier Airlines flight, departing Fri, Aug 22 from Seattle to Ontario, returning Tue, Aug 26, priced at $159 just found
Alaska Airlines
Sat, Oct 25 - Wed, Oct 29
SEA
Seattle
ONT
Ontario
$167 Roundtrip, just found
$167
Roundtrip
just found
Select Alaska Airlines flight, departing Sat, Oct 25 from Seattle to Ontario, returning Wed, Oct 29, priced at $167 just found
United
Wed, Aug 6 - Mon, Aug 11
SEA
Seattle
ONT
Ontario
$177 Roundtrip, just found
$177
Roundtrip
just found
Select United flight, departing Wed, Aug 6 from Seattle to Ontario, returning Mon, Aug 11, priced at $177 just found

Find the cheapest month to fly from Seattle (SEA) to Ontario (ONT)

October is typically the cheapest month to fly

From $65 - $197 per traveler.

Graph displaying average flight prices per month

Alternative airports near Ontario

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Los Angeles - Ontario Intl. ONT. Cheapest and Closest option available. Average driving time to city center is 8 minutes. Flights from $209
ONT
Los Angeles - Ontario Intl.
CheapestClosest
Average driving time to city center8 min
Flights from $209
Flights from Seattle (SEA) to Ontario (ONT)
Origin airport
Seattle - Tacoma Intl.
Destination airport
Los Angeles - Ontario Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, United
Roundtrip price
$118
Distance
956 mi
Average flight time
2 hours 47 mins

Seattle to Ontario Flights

The cheapest times to fly from Seattle to Ontario

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Seattle to Ontario are during the month of July. You can find some of the cheapest flights from Seattle to Ontario with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Seattle to Ontario

Sunday is one of the best days to book for cheap flights from Seattle to Ontario: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Seattle to Ontario

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Seattle to Ontario in 2025. You can also book with separate airlines for your outbound and return journeys, from $84 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Seattle to Ontario flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Seattle to Ontario airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) cost?
Score cheap return fares from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) starting at $130. Reserve your seat and get ready to go. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Frontier Airlines flight leaving SEA on July 29 2025 and touching down at ONT. The price was last updated on July 8 2025 and has not changed since.
What is the cheapest month to fly from SEA to ONT?
The cheapest flights from SEA to ONT are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Skip the layovers and fly straight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) with 3 carriers, including:

  • Alaska Airlines
  • Delta Air Lines
  • Frontier Airlines

What is the cheapest airline that flies from SEA to ONT?
At the moment, the cheapest carrier operating one-way flights from SEA to ONT is Frontier Airlines. You can book a seat on this route from $65. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from SEA on August 27 2025. Prices were last updated on July 8 2025 and have not changed since.
How many flights per day from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Every day on average, 5 nonstop flights take off from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT). Choose the departure that best fits your schedule.
What are the most popular departure times for flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
The 12 PM departures from SEA to ONT are typically the busiest. Greater demand means you'll likely pay more for these departures. If you want to save on your trip, pick a less crowded time to fly.
What day of the week has the most flights from SEA to ONT?
If you travel on a Thursday, you'll get the largest range of choices for flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT).
What is the earliest flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Seattle - Tacoma Intl. Airport (SEA)'s first flight to Los Angeles - Ontario Intl. Airport (ONT) departs at approximately 8:00AM UTC-8. With a total flight time of 2h 38m, you'll land at around 10:38AM UTC-8.
How long does it take to fly from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
It takes about 2 hours and 40 minutes to travel the 960 mi from SEA to ONT.
What airline has the least delays from SEA to ONT?
Consider booking with American Airlines if you'd like to fly straight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) without any holdups. This airline has the strongest track record for punctuality, with an on-time performance of 92%. Want to get notified of any changes? You can keep an eye on your flight status using the Expedia App.
What is the best time to fly from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
To land at Los Angeles - Ontario Intl. Airport (ONT) on time, pick a flight that leaves Seattle - Tacoma Intl. Airport (SEA) before 3 PM. The likelihood of cancellations is 22% higher, on average, for departures after this hour.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for Ontario from Seattle - Tacoma Intl. Airport (SEA)?
Hop on a direct flight from Seattle - Tacoma Intl. Airport (SEA) to Ontario and land at one of these hubs:

  • Los Angeles Intl. Airport (LAX)
  • John Wayne Airport (SNA)
  • Los Angeles - Ontario Intl. Airport (ONT)

Is it cheaper to buy a plane ticket from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) last-minute?
Holding off until just before your departure to book your flight from SEA to ONT often results in higher prices. While you might find some last-minute discounts, they're not always guaranteed. Keep your travel plans flexible for the best chance of scoring a bargain.
Is it cheaper to book a SEA to ONT flight and hotel package?
Booking a SEA to ONT flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip in one place. Pick from our impressive range of hotels and then add activities, car rentals and flights to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Generally, it's possible to reschedule or cancel your SEA to ONT flight. However, for bookings made more than 24 hours ago, additional charges may apply. Check your airline's policies in your itinerary to see what changes are possible and whether any costs are involved. You'll also find more details on our Customer Service portal.

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