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CA $199 Cheap Flights from Ontario Intl. Airport (ONT) to Seattle (SEA)

View CA $199 flight on Tue, Nov 3, 2026Opens in a new window

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

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Cheap flights from Ontario Intl. Airport (ONT) to Seattle (SEA)

Prices were available within the past 7 days and start at CA $199 for one-way flights and CA $371 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Sat, Oct 24 - Sat, Oct 31
ONT
Ontario
SEA
Seattle
CA $371 Roundtrip, found 4 days ago
CA $371
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Sat, Oct 24 from Ontario to Seattle, returning Sat, Oct 31, priced at CA $371 found 4 days ago
Delta
Sat, Nov 14 - Wed, Nov 18
ONT
Ontario
SEA
Seattle
CA $373 Roundtrip, found 14 hours ago
CA $373
Roundtrip
found 14 hours ago
Select Delta flight, departing Sat, Nov 14 from Ontario to Seattle, returning Wed, Nov 18, priced at CA $373 found 14 hours ago
Alaska Airlines
Sat, Oct 24 - Sat, Oct 31
ONT
Ontario
SEA
Seattle
CA $385 Roundtrip, found 4 days ago
CA $385
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Sat, Oct 24 from Ontario to Seattle, returning Sat, Oct 31, priced at CA $385 found 4 days ago
Alaska Airlines
Sat, Oct 17 - Wed, Nov 18
ONT
Ontario
SEA
Seattle
CA $385 Roundtrip, found 3 days ago
CA $385
Roundtrip
found 3 days ago
Select Alaska Airlines flight, departing Sat, Oct 17 from Ontario to Seattle, returning Wed, Nov 18, priced at CA $385 found 3 days ago
Alaska Airlines
Sat, Nov 14 - Wed, Nov 18
ONT
Ontario
SEA
Seattle
CA $387 Roundtrip, found 14 hours ago
CA $387
Roundtrip
found 14 hours ago
Select Alaska Airlines flight, departing Sat, Nov 14 from Ontario to Seattle, returning Wed, Nov 18, priced at CA $387 found 14 hours ago
Delta
Fri, Oct 16 - Sat, Oct 17
ONT
Ontario
SEA
Seattle
CA $390 Roundtrip, found 5 days ago
CA $390
Roundtrip
found 5 days ago
Select Delta flight, departing Fri, Oct 16 from Ontario to Seattle, returning Sat, Oct 17, priced at CA $390 found 5 days ago
Alaska Airlines
Thu, Nov 12 - Tue, Nov 17
ONT
Ontario
SEA
Seattle
CA $392 Roundtrip, found 4 days ago
CA $392
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Thu, Nov 12 from Ontario to Seattle, returning Tue, Nov 17, priced at CA $392 found 4 days ago
American Airlines
Sat, Oct 24 - Wed, Nov 18
ONT
Ontario
SEA
Seattle
CA $399 Roundtrip, found 3 days ago
CA $399
Roundtrip
found 3 days ago
Select American Airlines flight, departing Sat, Oct 24 from Ontario to Seattle, returning Wed, Nov 18, priced at CA $399 found 3 days ago
Southwest Airlines
Thu, Nov 12 - Tue, Nov 17
ONT
Ontario
SEA
Seattle
CA $502 Roundtrip, found 4 days ago
CA $502
Roundtrip
found 4 days ago
Select Southwest Airlines flight, departing Thu, Nov 12 from Ontario to Seattle, returning Tue, Nov 17, priced at CA $502 found 4 days ago
United
Sat, Oct 24 - Sun, Oct 25
ONT
Ontario
SEA
Seattle
CA $562 Roundtrip, found 12 hours ago
CA $562
Roundtrip
found 12 hours ago
Select United flight, departing Sat, Oct 24 from Ontario to Seattle, returning Sun, Oct 25, priced at CA $562 found 12 hours ago

Alternative airports near Seattle

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

Select flight to Seattle - Tacoma Intl. SEA. Cheapest option available. Average driving time to city centre is 20 minutes. Flights from CA $680
SEA
Seattle - Tacoma Intl.
Cheapest
Average driving time to city centre20 min
Flights from CA $680

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

August is typically the cheapest month to fly

From CA $129 - CA $395 per traveller.

Frequently asked questions

How much does a flight from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) cost?
You can find cheap one-way flights from CA $199 and cheap return flights from CA $371 ONT to SEA with Expedia. One-way flights typically cost between CA$164 and CA$796, and return flights often range between CA$669 and CA$1591. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when ONT to SEA ticket fares go up or down.
What is the cheapest month to fly from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
If you're looking for the cheapest time to fly from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.), February is typically your best bet. You can expect average return fares around CA$343 during this month. February often sees lower prices because it falls outside of peak holiday travel, when demand tends to drop. Other budget-friendly months to consider for this route include March and September.
Which airlines fly direct from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
There are 4 airlines offering direct flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.). Here are some of the top carriers:
  • Delta operates 27 direct flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) every week.
  • Frontier Airlines operates 7 direct flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) every week.
  • Japan Airlines operates 7 direct flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) every week.
  • Qatar Airways operates 7 direct flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) every week.
How do I find cheap flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA)?
To find a cheap flight from Ontario Intl. Airport (ONT) to Seattle, WA (SEA), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best airline to fly with from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The best airline to fly with from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) will differ from traveler to traveler. If you like to fly early, Alaska Airlines offers early morning flights. If price is the most important factor, Frontier Airlines typically offers the lowest fares. Southwest Airlines offers the most daily flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.), which is great if flexibility is what you value most. The best carrier for this journey could also be the one you have a loyalty membership with, as flying with that airline or another airline within the same alliance could help you collect points or enjoy lounge access.
What is the best time to fly from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The best time to fly from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) is typically February or September. These months offer a great balance, with return flights averaging around CA$343.
How many flights per day from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
You'll find around 5 nonstop flights per day from Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. (SEA). For even more choices, look at flights that include layovers, as there are approximately 72 connecting flights per day. Some common connection points include San Francisco Intl. (SFO), Portland Intl. (PDX), and Sky Harbor Intl. (PHX).
What is the earliest flight from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The earliest flight from Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. (SEA) typically departs around 12:55 AM local time, operated by American Airlines. This is a seasonal service active in September. An early departure like this can help you make the most of your time at your destination. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What day of the week has the most flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
You'll typically find the most flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) on a Friday, with around 58 flights available. This gives you plenty of options for your travel plans. Major airlines on this route include Southwest Airlines, Alaska Airlines, and Delta. Friday offers notably more flight options compared to other days of the week, so you have a good selection to choose from.
What are the most popular departure times for flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The most popular departure times for flights from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) are in the morning, from 6am to 9am. Many major carriers, including Alaska Airlines, Southwest Airlines and Delta, offer flights during this window. Many travellers prefer these early morning flights as they allow you to arrive at your destination with plenty of time to start your day.
How long does it take to fly from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
When flying from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.), you have a few options. A nonstop flight typically takes around 3 hours, covering a distance of approximately 1540 kilometres. If you opt for a one-stop flight, your travel time will be longer, usually around 8 hours 30 minutes. Flights with two or more stops generally take even longer, averaging about 12 hours. Keep in mind that actual flight times can vary due to factors like wind patterns and air traffic, so it's always a good idea to allow for some extra time when planning your trip.
Can you fly business or first class from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
You can fly business class or first class between ONT and SEA. You can fly business class with Frontier Airlines and Delta.First class cabins are available on Alaska Airlines, Delta, United, and American Airlines.
How do I earn miles on a Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight with Expedia?
It's easy to earn miles on a Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for Seattle, WA (SEA) from Ontario Intl. Airport (ONT)?
If you're planning to travel to Seattle from Los Angeles - Ontario Intl. (ONT), you can fly directly into Seattle - Tacoma Intl. (SEA). Some flights may connect through major hubs like San Francisco Intl. (SFO), Seattle - Tacoma Intl. (SEA), or Portland Intl. (PDX) before reaching Seattle. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) at the last minute?
Typically, booking a last minute flight from Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight and hotel package?
Securing a Ontario Intl. Airport (ONT) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Ontario Intl. Airport (ONT) to Seattle, WA (SEA)?
If you booked your Ontario Intl. Airport (ONT) to Seattle, WA (SEA) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Ontario Intl. Airport
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, United
Roundtrip price
CA $371
Distance
1530 km
Average flight time
2 hours 55 mins

Book with confidence

Los Angeles to Seattle Flights

The easy way to book your flights from Ontario Intl. Airport to Seattle 

With Expedia, it’s simple to find and book flights to Seattle from Ontario Intl. Airport whether you’re traveling for business or pleasure. Enter your travel dates, hit search, and choose your flight from 20 airlines that cover this route. There are nonstop flights to Seattle - Tacoma Intl., too.  

Choose your preferred carrier and cabin class with the advanced search tool and select your ideal departure time. Then, if you want, you can see just nonstop or refundable flights. And if you’re traveling last minute, just enter the date to check out flights from Ontario Intl. Airport to Seattle today, tomorrow, or this week.  

 

Save dollars with cheap flights from Ontario Intl. Airport, ONT to Seattle - Tacoma Intl., SEA 

Sort your search results by price to find great deals on your flight from Ontario Intl. Airport to Seattle—you get all your cheapest options first. Grab yourself a bargain now—the lowest price on flights to Seattle from Ontario Intl. Airport currently is just CA $371 rising to CA $562.  

Here are more money-saving tips: 

  • Fly in October when flight prices are normally at their lowest 
  • Book about a month to 6 weeks before you travel for the best prices to Seattle  
  • Avoid peak season and weekends when flights can cost more
  • Early morning and late-night flights are sometimes cheaper, so try varying your travel times 
  • One surefire way to save money on your flight is to book your flight and hotel together with Expedia. Sometimes, the savings are so large that the flight is basically free! 

 

Reasons to choose Expedia for your flight to Seattle from Ontario Intl. Airport 

Whatever your destination, budget, or reason to travel, in just one quick search, you can choose from loads of flights, airlines, and cabin classes. The filters make it quick and easy to find your ideal flights, and if you choose one of the flexible options, you won’t be charged to change your flight. So book your flight to Seattle with Expedia today.

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