$49 Cheap Flights from Seattle (SEA) to Ontario (ONT)

View $49 flight on Sat, Jun 7, 2025Opens in a new window

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

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Find available prices by choosing your travel dates.

Cheap Flights from Seattle to Ontario (SEA-ONT)

Prices were available within the past 7 days and start at $49 for one-way flights and $98 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Wed, May 28 - Sat, May 31
SEA
Seattle
ONT
Ontario
$98 Roundtrip, found 2 hours ago
$98
Roundtrip
found 2 hours ago
Select Frontier Airlines flight, departing Wed, May 28 from Seattle to Ontario, returning Sat, May 31, priced at $98 found 2 hours ago
Frontier Airlines
Sat, May 24 - Wed, May 28
SEA
Seattle
ONT
Ontario
$100 Roundtrip, found 1 hour ago
$100
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Sat, May 24 from Seattle to Ontario, returning Wed, May 28, priced at $100 found 1 hour ago
Frontier Airlines
Wed, Jun 11 - Tue, Jun 17
SEA
Seattle
ONT
Ontario
$103 Roundtrip, just found
$103
Roundtrip
just found
Select Frontier Airlines flight, departing Wed, Jun 11 from Seattle to Ontario, returning Tue, Jun 17, priced at $103 just found
Frontier Airlines
Tue, Jun 10 - Tue, Jun 17
SEA
Seattle
ONT
Ontario
$105 Roundtrip, found 5 hours ago
$105
Roundtrip
found 5 hours ago
Select Frontier Airlines flight, departing Tue, Jun 10 from Seattle to Ontario, returning Tue, Jun 17, priced at $105 found 5 hours ago
Frontier Airlines
Wed, Jun 4 - Sun, Jun 8
SEA
Seattle
ONT
Ontario
$108 Roundtrip, just found
$108
Roundtrip
just found
Select Frontier Airlines flight, departing Wed, Jun 4 from Seattle to Ontario, returning Sun, Jun 8, priced at $108 just found
Frontier Airlines
Sun, May 25 - Wed, May 28
SEA
Seattle
ONT
Ontario
$110 Roundtrip, found 1 hour ago
$110
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Sun, May 25 from Seattle to Ontario, returning Wed, May 28, priced at $110 found 1 hour ago
Alaska Airlines
Tue, May 20 - Tue, May 27
SEA
Seattle
ONT
Ontario
$128 Roundtrip, found 1 hour ago
$128
Roundtrip
found 1 hour ago
Select Alaska Airlines flight, departing Tue, May 20 from Seattle to Ontario, returning Tue, May 27, priced at $128 found 1 hour ago
United
Mon, May 19 - Tue, May 27
SEA
Seattle
ONT
Ontario
$133 Roundtrip, found 4 hours ago
$133
Roundtrip
found 4 hours ago
Select United flight, departing Mon, May 19 from Seattle to Ontario, returning Tue, May 27, priced at $133 found 4 hours ago
Delta
Wed, May 21 - Wed, May 28
SEA
Seattle
ONT
Ontario
$157 Roundtrip, found 1 hour ago
$157
Roundtrip
found 1 hour ago
Select Delta flight, departing Wed, May 21 from Seattle to Ontario, returning Wed, May 28, priced at $157 found 1 hour ago
American Airlines
Sat, Jun 7 - Tue, Jun 10
SEA
Seattle
ONT
Ontario
$187 Roundtrip, found 11 hours ago
$187
Roundtrip
found 11 hours ago
Select American Airlines flight, departing Sat, Jun 7 from Seattle to Ontario, returning Tue, Jun 10, priced at $187 found 11 hours ago

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 $98. 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 May 19 2025 and touching down at ONT. The price was last updated on April 24 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 $49. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from SEA on June 7 2025. Prices were last updated on April 24 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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