S$141 Cheap Flights from Seattle to Ontario

View S$141 flight on Thu, 14 May, 2026Opens in a new window

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

  • notification illustration

    Be in the know

    Get alerts if flight prices drop or rise*
  • deals illustration

    Book smarter

    Save up to 40% on select hotels after you book a flight*
  • trophy illustration

    Earn twice

    Earn your airline miles on top of our rewards
    Sign in

Cheap Flights from Seattle to Ontario (SEA-ONT)

Prices were available within the past 7 days and start at S$141 for one-way flights and S$254 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$254 Return, found 6 days ago
S$254
Return
found 6 days ago
Select Delta flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$254 found 6 days ago
Delta
Wed, 21 Jan - Wed, 28 Jan
SEA
Seattle
ONT
Ontario
S$255 Return, found 6 days ago
S$255
Return
found 6 days ago
Select Delta flight, departing Wed, 21 Jan from Seattle to Ontario, returning Wed, 28 Jan, priced at S$255 found 6 days ago
Delta
Sat, 17 Jan - Wed, 28 Jan
SEA
Seattle
ONT
Ontario
S$307 Return, found 6 days ago
S$307
Return
found 6 days ago
Select Delta flight, departing Sat, 17 Jan from Seattle to Ontario, returning Wed, 28 Jan, priced at S$307 found 6 days ago
Delta
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$319 Return, found 6 days ago
S$319
Return
found 6 days ago
Select Delta flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$319 found 6 days ago
Delta
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$352 Return, found 6 days ago
S$352
Return
found 6 days ago
Select Delta flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$352 found 6 days ago
Delta
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$357 Return, found 6 days ago
S$357
Return
found 6 days ago
Select Delta flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$357 found 6 days ago
Delta
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$370 Return, found 6 days ago
S$370
Return
found 6 days ago
Select Delta flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$370 found 6 days ago
United
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$396 Return, found 6 days ago
S$396
Return
found 6 days ago
Select United flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$396 found 6 days ago
American Airlines
Thu, 14 May - Sun, 17 May
SEA
Seattle
ONT
Ontario
S$480 Return, found 6 days ago
S$480
Return
found 6 days ago
Select American Airlines flight, departing Thu, 14 May from Seattle to Ontario, returning Sun, 17 May, priced at S$480 found 6 days ago
Alaska Airlines
Tue, 20 Jan - Wed, 21 Jan
SEA
Seattle
ONT
Ontario
S$485 Return, found 1 day ago
S$485
Return
found 1 day ago
Select Alaska Airlines flight, departing Tue, 20 Jan from Seattle to Ontario, returning Wed, 21 Jan, priced at S$485 found 1 day ago

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

October is typically the cheapest month to fly

From S$102 - S$207 per traveller.

Frequently asked questions

How much is a flight from Seattle - Tacoma Intl. Airport (SEA) to ONT?
Based on airfares available within the last 7 days on Expedia for flights departing within the next year, round-trip flights between Sea-Tac Airport and Los Angeles - Ontario Intl. Airport (ONT) start from S$254. Make your booking ASAP to score the best price for your big adventure. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from SEA to Los Angeles - Ontario Intl. Airport (ONT)?
The majority of flights can be cancelled online, but every airline has its own set of terms and conditions. If you do need to cancel your flight, check out our Customer Service Portal and follow the instructions.
How do I find cheap flights from SEA to Los Angeles - Ontario Intl. Airport (ONT) that have flexible change policies?
Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) flights, you'll see a "no change fees" filter for you to select.
How far is the flight from Sea-Tac Airport to ONT?
The flying distance between Sea-Tac Airport and Los Angeles - Ontario Intl. Airport (ONT) is 1,550 kilometres. Close your eyes or get stuck into a book and the journey will zip on by.
Which airlines fly direct from Sea-Tac Airport to Ontario Airport?
One airline that services the route from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) is Alaska Airlines (AS). It offers 117 flights every month. Another carrier servicing this route is Delta Air Lines (DL). You'll have 86 flights each month to select from.
Are SEA to ONT flight tickets cheaper when they're purchased at the last minute?
It is possible to nab a fantastic last-minute deal from SEA to Ontario Airport, but it can also be hit-or-miss. As many airlines release prices up to a year in advance, it's worthwhile keeping an eye on fares early and being ready to book when you see a bargain. Expedia compares carrier prices and updates flight deals often, so you can rest easy knowing you're always getting the latest offers.

Travel information

Origin airport
Seattle - Tacoma Intl.
Destination airport
Los Angeles - Ontario Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, United
Return price
S$254
Distance
1530 km
Average flight time
2 hours 39 mins

Book with confidence

Perfect flights from Seattle to Ontario

Your Journey from Seattle to Ontario

Start your unforgettable journey with Expedia. Our broad selection of flights from Seattle to Ontario caters to every travel need. Whether you're yearning for a romantic escape, a solo adventure, or a cultural immersion, we've got you covered.
 

Choosing Your Ideal Flight

With Expedia, you have access to a wide range of airlines, including Delta, Alaska Airlines, United, American Airlines. Our selection of flights from Seattle - Tacoma Intl. to Los Angeles - Ontario Intl. caters to every traveler's requirements, ensuring your journey aligns with your schedule. With options from 20 airlines, you're bound to find the perfect flight.
 

Maximizing Value with Seattle to Ontario Flights

Experience the joy of finding cheap flights from Seattle - Tacoma Intl. to Los Angeles - Ontario Intl. that fit your budget. Keep an eye out for our special deals and discounts, and check our flexible one-way fares from S$141 and roundtrip prices from S$254*.
 

Pre-Flight Essentials

Ensure a smooth journey from Seattle to Ontario with Expedia. From information about check-in times and in-flight amenities to guidance on baggage policies, we provide all the essentials to prepare you for your flight.
 

Experience the Vibrant Ontario

Picture yourself stepping off the plane in Ontario and immersing yourself in the unique atmosphere of . From local markets to cultural festivals, each city offers its distinct charm. Make the most of your trip by exploring local attractions and indulging in the local cuisine. With Expedia, explore all this and more, tailored to your budget.
 

Added Convenience on Your Seattle to Ontario Flight

Traveling with Expedia is more than just a flight. We offer details about in-flight amenities, baggage policies, and more to ensure a smooth and hassle-free journey. Choose from our variety of airlines and embark on a memorable journey from Seattle to Ontario.
 

Beyond the Flight – Exploring Ontario

With Expedia, your adventure extends beyond the flight. Explore Ontario at your own pace by renting a car or booking a hotel. Discover hidden gems off the beaten path and create unforgettable memories.
 

Book Your Flight from Seattle to Ontario with Confidence

Planning your next great adventure is a breeze with Expedia. Our user-friendly platform, unbeatable prices, and round-the-clock customer support make your travel experience seamless and stress-free. Embark on your journey from Seattle to Ontario with confidence. Book your travel arrangements with Expedia today.
 
*Note: Prices may vary based on availability and are subject to change.
Perfect flights from Seattle to Ontario

Explore a world of travel with Expedia

*Available to Expedia members.