$56 Cheap Flights from Seattle (SEA) to Ontario (ONT)

View $56 flight on Wed, Nov 19, 2025Opens in a new window

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

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Today's featured flight deals from Seattle-Tacoma International Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)

Nonstop
Carry-on included
Lower price than typical

Cheap Flights from Seattle to Ontario (SEA-ONT)

Prices were available within the past 7 days and start at $56 for one-way flights and $81 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Sun, Jan 4 - Fri, Jan 9
SEA
Seattle
ONT
Ontario
$81 Roundtrip, found 6 hours ago
$81
Roundtrip
found 6 hours ago
Select Frontier Airlines flight, departing Sun, Jan 4 from Seattle to Ontario, returning Fri, Jan 9, priced at $81 found 6 hours ago
Frontier Airlines
Mon, Dec 15 - Tue, Dec 23
SEA
Seattle
ONT
Ontario
$104 Roundtrip, found 1 day ago
$104
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Mon, Dec 15 from Seattle to Ontario, returning Tue, Dec 23, priced at $104 found 1 day ago
Frontier Airlines
Sat, Nov 15 - Sat, Nov 22
SEA
Seattle
ONT
Ontario
$106 Roundtrip, found 1 hour ago
$106
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Sat, Nov 15 from Seattle to Ontario, returning Sat, Nov 22, priced at $106 found 1 hour ago
Frontier Airlines
Tue, Dec 30 - Mon, Jan 5
SEA
Seattle
ONT
Ontario
$107 Roundtrip, found 3 hours ago
$107
Roundtrip
found 3 hours ago
Select Frontier Airlines flight, departing Tue, Dec 30 from Seattle to Ontario, returning Mon, Jan 5, priced at $107 found 3 hours ago
Frontier Airlines
Sun, Jan 4 - Wed, Jan 7
SEA
Seattle
ONT
Ontario
$109 Roundtrip, found 10 hours ago
$109
Roundtrip
found 10 hours ago
Select Frontier Airlines flight, departing Sun, Jan 4 from Seattle to Ontario, returning Wed, Jan 7, priced at $109 found 10 hours ago
Frontier Airlines
Sat, Nov 22 - Wed, Nov 26
SEA
Seattle
ONT
Ontario
$110 Roundtrip, found 1 hour ago
$110
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Sat, Nov 22 from Seattle to Ontario, returning Wed, Nov 26, priced at $110 found 1 hour ago
Alaska Airlines
Wed, Dec 10 - Mon, Jan 5
SEA
Seattle
ONT
Ontario
$123 Roundtrip, found 19 hours ago
$123
Roundtrip
found 19 hours ago
Select Alaska Airlines flight, departing Wed, Dec 10 from Seattle to Ontario, returning Mon, Jan 5, priced at $123 found 19 hours ago
United
Wed, Dec 31 - Mon, Jan 5
SEA
Seattle
ONT
Ontario
$133 Roundtrip, found 6 hours ago
$133
Roundtrip
found 6 hours ago
Select United flight, departing Wed, Dec 31 from Seattle to Ontario, returning Mon, Jan 5, priced at $133 found 6 hours ago
Delta
Tue, Jan 27 - Tue, Feb 3
SEA
Seattle
ONT
Ontario
$177 Roundtrip, found 1 hour ago
$177
Roundtrip
found 1 hour ago
Select Delta flight, departing Tue, Jan 27 from Seattle to Ontario, returning Tue, Feb 3, priced at $177 found 1 hour ago
Southwest Airlines
Mon, Jan 12 - Tue, Jan 13
SEA
Seattle
ONT
Ontario
$183 Roundtrip, found 14 hours ago
$183
Roundtrip
found 14 hours ago
Select Southwest Airlines flight, departing Mon, Jan 12 from Seattle to Ontario, returning Tue, Jan 13, priced at $183 found 14 hours ago

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

November is typically the cheapest month to fly

From $79 - $231 per traveler.

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 $223
ONT
Los Angeles - Ontario Intl.
CheapestClosest
Average driving time to city center8 min
Flights from $223

Frequently asked questions

How much does a flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) cost?
Get a cheap one-way flight from $56 or cheap return flight from $81 from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight offers on this route.
What is the cheapest month to fly from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Traveling in January can help you save, as it's the cheapest month for flights between SEA and ONT. You'll often find the lowest fares during off-peak months.
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 Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
The cheapest airline to offer flights between Seattle - Tacoma Intl. Airport (SEA) and Los Angeles - Ontario Intl. Airport (ONT) can change depending on your travel plans. Frontier Airlines and Delta Air Lines are just some well-known options offering well-priced fares. Use Expedia's filter tool to compare airlines in one place and find the right SEA to ONT flight that fits your budget.
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.

Travel information

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
$72
Distance
956 mi
Average flight time
2 hours 42 mins

Book with confidence

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 January. 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 $56 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.

 

Seattle to Ontario Flights

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*Available to One Key members.