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CA $151 Cheap Flights from Seattle (SEA) to Ontario Intl. Airport (ONT)

View CA $151 flight on Mon, Oct 19, 2026Opens in a new window

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

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

Prices were available within the past 7 days and start at CA $151 for one-way flights and CA $218 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Sat, Oct 3 - Fri, Oct 16
SEA
Seattle
ONT
Ontario
CA $218 Roundtrip, found 9 hours ago
CA $218
Roundtrip
found 9 hours ago
Select Delta flight, departing Sat, Oct 3 from Seattle to Ontario, returning Fri, Oct 16, priced at CA $218 found 9 hours ago
Delta
Wed, Oct 21 - Wed, Oct 28
SEA
Seattle
ONT
Ontario
CA $232 Roundtrip, just found
CA $232
Roundtrip
just found
Select Delta flight, departing Wed, Oct 21 from Seattle to Ontario, returning Wed, Oct 28, priced at CA $232 just found
Delta
Wed, Oct 21 - Wed, Oct 28
SEA
Seattle
ONT
Ontario
CA $246 Roundtrip, just found
CA $246
Roundtrip
just found
Select Delta flight, departing Wed, Oct 21 from Seattle to Ontario, returning Wed, Oct 28, priced at CA $246 just found
Delta
Wed, Oct 21 - Wed, Oct 28
SEA
Seattle
ONT
Ontario
CA $295 Roundtrip, just found
CA $295
Roundtrip
just found
Select Delta flight, departing Wed, Oct 21 from Seattle to Ontario, returning Wed, Oct 28, priced at CA $295 just found
Delta
Mon, Nov 9 - Fri, Nov 13
SEA
Seattle
ONT
Ontario
CA $301 Roundtrip, found 10 hours ago
CA $301
Roundtrip
found 10 hours ago
Select Delta flight, departing Mon, Nov 9 from Seattle to Ontario, returning Fri, Nov 13, priced at CA $301 found 10 hours ago
Delta
Wed, Oct 21 - Wed, Oct 28
SEA
Seattle
ONT
Ontario
CA $309 Roundtrip, just found
CA $309
Roundtrip
just found
Select Delta flight, departing Wed, Oct 21 from Seattle to Ontario, returning Wed, Oct 28, priced at CA $309 just found
Alaska Airlines
Wed, Oct 21 - Wed, Oct 28
SEA
Seattle
ONT
Ontario
CA $337 Roundtrip, just found
CA $337
Roundtrip
just found
Select Alaska Airlines flight, departing Wed, Oct 21 from Seattle to Ontario, returning Wed, Oct 28, priced at CA $337 just found
American Airlines
Wed, Nov 11 - Sat, Nov 14
SEA
Seattle
ONT
Ontario
CA $371 Roundtrip, just found
CA $371
Roundtrip
just found
Select American Airlines flight, departing Wed, Nov 11 from Seattle to Ontario, returning Sat, Nov 14, priced at CA $371 just found
United
Wed, Nov 11 - Sat, Nov 14
SEA
Seattle
ONT
Ontario
CA $481 Roundtrip, just found
CA $481
Roundtrip
just found
Select United flight, departing Wed, Nov 11 from Seattle to Ontario, returning Sat, Nov 14, priced at CA $481 just found
Southwest Airlines
Fri, Feb 5 - Tue, Feb 9
SEA
Seattle
ONT
Ontario
CA $503 Roundtrip, found 5 days ago
CA $503
Roundtrip
found 5 days ago
Select Southwest Airlines flight, departing Fri, Feb 5 from Seattle to Ontario, returning Tue, Feb 9, priced at CA $503 found 5 days ago

Alternative airports near Ontario

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

Select flight to John Wayne SNA. Average driving time to city centre is 42 minutes. Flights from CA $576
SNA
John Wayne
Average driving time to city centre42 min
Flights from CA $576

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

August is typically the cheapest month to fly

From CA $123 - CA $348 per traveller.

Frequently asked questions

How much does a flight from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) cost?
You can find cheap one-way flights from CA $151 and cheap return flights from CA $218 SEA to ONT with Expedia. One-way flights typically cost between CA$216 and CA$869, and return flights often range between CA$342 and CA$1417. 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 SEA to ONT ticket fares go up or down.
What is the cheapest month to fly from Seattle, WA (SEA) to Ontario Intl. Airport (ONT)?
The cheapest months to fly from Seattle, WA (SEA) to Ontario Intl. Airport (ONT) are typically during off-peak season when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you are able to. Use the calendar view in your search to see which months have low fares on this route.
Which airlines fly direct from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
There are 2 airlines offering direct flights from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT). Here are the carriers:
  • Delta operates 31 direct flights from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) every week.
  • Frontier Airlines operates 7 direct flights from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) every week.
How do I find cheap flights from Seattle, WA (SEA) to Ontario Intl. Airport (ONT)?
To find a cheap flight from Seattle, WA (SEA) to Ontario Intl. Airport (ONT), 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 Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
The best airline to fly with from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) will differ from traveler to traveler. If you like to fly early, Delta offers early morning flights. If price is the most important factor, Southwest Airlines typically offers the lowest fares. Southwest Airlines offers the most daily flights from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT), 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 Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
How many flights per day from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
You'll find around 5 nonstop flights per day from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT). For even more choices, look at flights that include layovers, as there are approximately 70 connecting flights per day. Some common connection points include Denver Intl. (DEN), Portland Intl. (PDX), and Sky Harbor Intl. (PHX).
What is the earliest flight from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
The earliest flight from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) typically departs around 12:25 AM. This flight is operated by American Airlines. This is a seasonal service, active only in September. An early departure like this can be great if you want to maximize 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 Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
You'll find the most flights from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) on a Friday, with around 63 flights available. This gives you a good selection of options for your travel plans. Major airlines on this route include Alaska Airlines, Southwest Airlines, and United. Flight options are notably more plentiful on Fridays compared to other days of the week, offering you more flexibility.
What are the most popular departure times for flights from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
The most popular departure times for flights from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) 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 this because it allows for an early start to their journey, giving them more time at their destination.
How long does it take to fly from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
A nonstop flight from Seattle - Tacoma Intl. (SEA) to Ontario Intl. Airport (ONT) typically takes around 2 hours 48 minutes. This route covers a distance of approximately 1540 kilometres. If you opt for a flight with one stop, your travel time will be longer, usually around 5 hours. Flights with two or more stops generally take about 11 hours 30 minutes. 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 journey.
Can you fly business or first class from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT)?
Yes, you can fly business class or first class between Seattle - Tacoma Intl. (SEA) and Ontario Intl. Airport (ONT).Airlines that offer business class service on this route include:
  • Frontier Airlines
  • Alaska Airlines
  • Delta
First class cabins are available on:
  • Alaska Airlines
  • Delta
  • Hawaiian Airlines
  • United
  • American Airlines
How do I earn miles on a Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) flight with Expedia?
It's easy to earn miles on a Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) 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 Ontario Intl. Airport (ONT) from Seattle, WA (SEA)?
If you're planning to travel to Ontario from Seattle - Tacoma Intl. (SEA), you can fly directly into Los Angeles - Ontario Intl. (ONT). Some flights may connect through major hubs like Denver Intl. (DEN), Los Angeles Intl. (LAX), or Harry Reid International Airport (LAS) before reaching Ontario. 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 Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) at the last minute?
Typically, booking a last minute flight from Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) 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 Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) flight and hotel package?
Securing a Seattle, WA (SEA-Seattle - Tacoma Intl.) to Ontario Intl. Airport (ONT) 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 Seattle, WA (SEA) to Ontario Intl. Airport (ONT)?
If you booked your Seattle, WA (SEA) to Ontario Intl. Airport (ONT) 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
Seattle - Tacoma Intl.
Destination airport
Ontario Intl. Airport
Airlines serving
Alaska Airlines, American Airlines, Delta, United
Roundtrip price
CA $218
Distance
1530 km
Average flight time
2 hours 54 mins

Book with confidence

Seattle to Los Angeles Flights

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

With Expedia, it’s simple to find and book flights to Ontario Intl. Airport from Seattle 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 Ontario Intl. Airport, 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 Seattle to Ontario Intl. Airport today, tomorrow, or this week.  

 

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

Sort your search results by price to find great deals on your flight from Seattle to Ontario Intl. Airport—you get all your cheapest options first. Grab yourself a bargain now—the lowest price on flights to Ontario Intl. Airport from Seattle currently is just CA $218 rising to CA $503.  

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 Ontario Intl. Airport  
  • 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 Ontario Intl. Airport from Seattle 

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 Ontario Intl. Airport with Expedia today.

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