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Cheap flights from Ontario to Seattle from C$ 214

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 28/9. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
17 Sep — 24 Sep1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ontario to Seattle

Enter your travel dates to find the best prices.

Cheapest flights from Ontario to Seattle
Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 18 August 2026.

Fri 11/912:25 p.m. -
2 stops9h 20m
Sat 12/97:35 p.m. -
1 stop7h 00m
Deal found 13/8C$ 352
Fri 4/912:25 p.m. -
2 stops11h 35m
Tue 8/97:00 a.m. -
1 stop7h 15m
Deal found 14/8C$ 355
Sat 12/91:20 p.m. -
1 stop8h 25m
Wed 16/97:35 p.m. -
1 stop7h 00m
Deal found 14/8C$ 362
Tue 15/96:45 a.m. -
2 stops15h 00m
Tue 22/97:35 p.m. -
1 stop8h 30m
Deal found 18/8C$ 381
Sat 19/97:15 a.m. -
1 stop14h 30m
Sat 26/97:35 p.m. -
1 stop8h 30m
Deal found 17/8C$ 391
Fri 4/96:10 p.m. -
1 stop18h 30m
Tue 8/97:00 a.m. -
1 stop7h 15m
Deal found 14/8C$ 392
Mon 14/95:30 p.m. -
1 stop19h 10m
Mon 21/97:35 p.m. -
1 stop8h 30m
Deal found 17/8C$ 392
Fri 18/98:00 p.m. -
1 stop16h 40m
Mon 28/97:35 p.m. -
1 stop8h 30m
Deal found 17/8C$ 394
Sun 13/95:30 p.m. -
1 stop19h 10m
Tue 15/97:35 p.m. -
1 stop8h 30m
Deal found 17/8C$ 398
Mon 28/96:45 a.m. -
2 stops15h 00m
Fri 2/107:35 p.m. -
1 stop8h 30m
Deal found 17/8C$ 399
Mon 28/96:55 a.m. -
2 stops14h 50m
Mon 5/107:35 p.m. -
1 stop7h 00m
Deal found 14/8C$ 402
Tue 8/98:00 p.m. -
1 stop25h 45m
Fri 11/97:35 p.m. -
1 stop8h 30m
Deal found 17/8C$ 403

Find flight deals from Ontario to Seattle

Keep the following information in mind while searching for Ontario to Seattle flight deals. Data was last updated 18 August 2026.

Round-trip from

C$ 352

One-way from

C$ 214

Popular in

June

Cheapest in

February

Average price

C$ 624

Good round-trip deal

C$ 636 or less

Good one-way deal

C$ 350 or less
WestJet
  • WestJet
  • 11/9-12/9
  • 3 total stops
  • 16h 20m total
  • Ontario to Seattle
Search Deals
WestJet
  • WestJet
  • 28/9
  • 2 total stops
  • 9h 20m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 13% potential increase in price (C$ 112 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 21 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in August 2026
Search Deals
Price to beat on a round-trip flight from Ontario to Seattle/Tacoma Intl.
Search Deals
Price to beat on a one-way flight from Ontario to Seattle/Tacoma Intl.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 18 August 2026.
Use the filters below to find and compare flights from Ontario to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

MontrealSeattle

YUL Montreal Pierre Elliott Trudeau Intl - SEA Seattle/Tacoma Intl

YULSEA

Montreal Pierre Elliott Trudeau Intl

Fri 18/9

5:45 p.m.-6:45 p.m.

2 stops28h 00m

Seattle/Tacoma Intl

Mon 28/9

7:35 p.m.-7:05 a.m.

1 stop8h 30m

C$ 410

MontrealSeattle

YUL Montreal Pierre Elliott Trudeau Intl - SEA Seattle/Tacoma Intl

YULSEA

Montreal Pierre Elliott Trudeau Intl

Mon 14/9

5:45 p.m.-9:40 a.m.

2 stops18h 55m

Seattle/Tacoma Intl

Mon 21/9

7:35 p.m.-7:05 a.m.

1 stop8h 30m

C$ 412

OttawaSeattle

YOW Ottawa - SEA Seattle/Tacoma Intl

YOWSEA

Ottawa

Wed 30/9

6:55 a.m.-6:45 p.m.

2 stops14h 50m

Seattle/Tacoma Intl

Sun 4/10

7:35 p.m.-5:35 a.m.

1 stop7h 00m

C$ 419

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Sun 13/9

6:10 p.m.-9:40 a.m.

1 stop18h 30m

Seattle/Tacoma Intl

Thu 17/9

7:35 p.m.-5:15 p.m.

1 stop18h 40m

C$ 437

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Thu 10/9

6:10 p.m.-9:40 a.m.

1 stop18h 30m

Seattle/Tacoma Intl

Tue 15/9

7:35 p.m.-5:15 p.m.

1 stop18h 40m

C$ 438

OttawaSeattle

YOW Ottawa - SEA Seattle/Tacoma Intl

YOWSEA

Ottawa

Fri 4/9

12:25 p.m.-9:00 p.m.

2 stops11h 35m

Seattle/Tacoma Intl

Tue 8/9

7:00 a.m.-12:30 p.m.

2 stops26h 30m

C$ 441

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Tue 8/9

6:10 p.m.-6:45 p.m.

1 stop27h 35m

Seattle/Tacoma Intl

Sun 13/9

7:35 p.m.-5:15 p.m.

1 stop18h 40m

C$ 473

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Thu 3/9

6:10 p.m.-9:00 p.m.

1 stop29h 50m

Seattle/Tacoma Intl

Sun 6/9

7:00 a.m.-5:15 p.m.

1 stop7h 15m

C$ 484

LondonSeattle

YXU London - SEA Seattle/Tacoma Intl

YXUSEA

London

Thu 24/9

5:55 p.m.-9:40 a.m.

1 stop18h 45m

Seattle/Tacoma Intl

Mon 28/9

7:35 p.m.-5:20 a.m.

1 stop6h 45m

C$ 485

MontrealSeattle

YUL Montreal Pierre Elliott Trudeau Intl - SEA Seattle/Tacoma Intl

YULSEA

Montreal Pierre Elliott Trudeau Intl

Thu 3/9

6:00 a.m.-2:34 p.m.

1 stop11h 34m

Seattle/Tacoma Intl

Sun 6/9

9:53 a.m.-11:30 p.m.

1 stop10h 37m

C$ 496

Flights are sorted by cheapest round-trip flights first.

Deals found on 13/8

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from Ontario to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Ontario with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Ontario to Seattle

What is the cheapest month to book a flight from Region of Ontario to Seattle?

Currently, February is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 347). Flying from Region of Ontario to Seattle in August is currently the most expensive (average of C$ 654). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from ON to SEA?

Find hourly flight availability from Ontario to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 18 August 2026.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Region of Ontario to Seattle as you normally would.

Weekly flight availability from Region of Ontario to Seattle

Explore weekly flight availability from Ontario to Seattle. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 18 August 2026.

The most flights from CAON to SEA are scheduled on a Monday (4 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (1 on average).

How much does it cost to fly round-trip from Region of Ontario to Seattle?

Airfare is below average for this route at the moment.
Region of Ontario to Seattle flights typically cost between C$ 524 and C$ 911 in September.
The cheapest round-trip price found within the last 5 days was C$ 476 on WestJet (8 Sep-13 Sep).

How far ahead should I book a flight from Region of Ontario to Seattle?

Booking 85 days in advance of your planned departure date is, on average, the best time to get cheap flights from Region of Ontario to Seattle. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

Related info for your journey

Find useful and relevant information for your journey from Ontario to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to Seattle from Ontario?

    Located just 18.4 km from the city centre, Seattle/Tacoma Intl (SEA) is the airport most travelers will use when flying to Seattle from Ontario.

  • How long is the flight from Region of Ontario to Seattle?

    Departing from Region of Ontario to Seattle will take you 11h 34m. The distance from Region of Ontario to Seattle is about 3663 km. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

  • What are the cheapest airlines to fly from Region of Ontario to Seattle one-way?

    For one-way options, check prices for WestJet. According to our data, you can fly for as low as C$ 122. Users have also found prices from C$ 164 and C$ 170 on United Airlines and Alaska Airlines, respectively.

  • What are the most popular routes from Region of Ontario to Seattle?

    The most popular route from Region of Ontario to Seattle is Toronto Pearson Intl - Seattle/Tacoma Intl. You may also consider Toronto Island - Seattle/Tacoma Intl or Hamilton - Seattle/Tacoma Intl.

  • What are the most reliable airlines from Region of Ontario to Seattle?

    No one likes to see their flight delayed. When booking a flight from Region of Ontario to Seattle consider choosing Alaska Airlines (88%), Brussels Airlines (41%) or Air Canada (40%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Region of Ontario to Seattle?

    Looking at all options, your cheapest flight can be booked for C$ 302. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 470 on average, our data indicates C$ 613 when flying from Region of Ontario to Seattle.

  • Can I find deals for flights from Ontario to Seattle that include hotel bookings?

    Yes. In addition to deals on Ontario to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to Seattle?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Seattle.

  • Can I find deals for business class flights from Ontario to Seattle?

    Yes. Cheapflights offers flight deals from Ontario to Seattle by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Region of Ontario to Seattle?

    Currently, February is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 347). Flying from Region of Ontario to Seattle in August is currently the most expensive (average of C$ 654). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Kent
Leavenworth
Mukilteo
Tacoma
Renton
Cashmere
Lynnwood
Ellensburg
Tukwila
Olympia
Marysville
Federal Way
Kirkland

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Alternative routes for Ontario to Seattle

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Ontario to Seattle

Discover the top 5 airlines that operate flights from Ontario to Seattle. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 18 August 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapestC$ 224AverageC$ 836FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Air CanadaCheapestC$ 250AverageC$ 622FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
United AirlinesCheapestC$ 266AverageC$ 658FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
WestJetCheapestC$ 269AverageC$ 486FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 269AverageC$ 426FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Ontario to Seattle?

900+ travel sites are searched through when a user searches for a flight using Cheapflights. From the search interface, users can use filters to choose airlines, airports, flight times, cabin classes and more to their preference. Book your flight to Seattle from Ontario today with Cheapflights!

Why should you use Cheapflights to find cheap flight tickets from Ontario to Seattle?

Millions of users choose and trust Cheapflights to book the best flight deals from Ontario to Seattle for free. We help you search and compare prices from hundreds of airlines for the right flight just for you.

Can Cheapflights find flights from Ontario to Seattle with no change fees?

Need flexible booking options for your flight to Seattle from Ontario? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

Can Cheapflights notify me if prices for flights from Ontario to Seattle become cheaper?

Of course! You can now track prices for flights from Ontario to Seattle and get an alert from Cheapflights when they change. Have a valid email address ready and click the bell icon next to the flight deals above to set up your price alerts.

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