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Cheap flights from Ontario to Seattle from C$ 252

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 13/9. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
12 Sep — 19 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 13 August 2026.

Tue 15/96:45 a.m. -
2 stops15h 00m
Tue 22/97:35 p.m. -
1 stop8h 30m
Deal found 13/8C$ 384
Tue 22/91:20 p.m. -
1 stop8h 25m
Wed 23/97:35 p.m. -
1 stop7h 00m
Deal found 12/8C$ 440
Thu 10/96:10 p.m. -
1 stop18h 30m
Thu 17/97:35 p.m. -
1 stop18h 40m
Deal found 12/8C$ 440
Sat 12/91:20 p.m. -
1 stop8h 25m
Sat 19/97:35 p.m. -
1 stop7h 00m
Deal found 10/8C$ 457
Sat 3/106:45 a.m. -
2 stops15h 00m
Sat 10/107:35 p.m. -
1 stop8h 30m
Deal found 10/8C$ 472
Sat 3/106:00 p.m. -
1 stop7h 42m
Sat 10/105:40 a.m. -
1 stop8h 14m
Deal found 10/8C$ 475
Wed 30/96:00 p.m. -
1 stop7h 47m
Wed 7/105:40 a.m. -
1 stop8h 14m
Deal found 10/8C$ 478
Tue 22/91:20 p.m. -
1 stop8h 25m
Fri 25/97:35 p.m. -
1 stop7h 00m
Deal found 12/8C$ 479
Wed 11/117:30 a.m. -
1 stop10h 07m
Sun 15/118:40 a.m. -
1 stop8h 53m
Deal found 8/8C$ 479
Thu 1/106:45 a.m. -
2 stops15h 00m
Sun 4/107:35 p.m. -
1 stop8h 30m
Deal found 8/8C$ 481
Thu 3/92:50 p.m. -
1 stop9h 10m
Sun 6/910:30 a.m. -
1 stop9h 15m
Deal found 10/8C$ 481
Tue 15/96:00 p.m. -
1 stop7h 47m
Tue 22/98:00 a.m. -
1 stop7h 52m
Deal found 12/8C$ 482

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 13 August 2026.

Round-trip from

C$ 384

One-way from

C$ 252

Popular in

June

Cheapest in

February

Average price

C$ 585

Good round-trip deal

C$ 565 or less

Good one-way deal

C$ 347 or less
WestJet
  • WestJet
  • 15/9-22/9
  • 3 total stops
  • 23h 30m total
  • Ontario to Seattle
Search Deals
WestJet
  • WestJet
  • 13/9
  • 1 total stop
  • 18h 30m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 14% potential increase in price (C$ 121 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% 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 13 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

Sat 12/9

6:00 a.m.-2:49 p.m.

1 stop11h 49m

Seattle/Tacoma Intl

Tue 15/9

8:59 a.m.-11:50 p.m.

1 stop11h 51m

C$ 483

MontrealSeattle

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

YULSEA

Montreal Pierre Elliott Trudeau Intl

Tue 15/9

6:00 a.m.-2:49 p.m.

1 stop11h 49m

Seattle/Tacoma Intl

Tue 22/9

9:43 a.m.-11:27 p.m.

1 stop10h 44m

C$ 485

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$ 486

MontrealSeattle

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

YULSEA

Montreal Pierre Elliott Trudeau Intl

Tue 3/11

12:50 p.m.-10:05 p.m.

1 stop12h 15m

Seattle/Tacoma Intl

Tue 10/11

11:45 a.m.-11:58 p.m.

1 stop9h 13m

C$ 495

MontrealSeattle

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

YULSEA

Montreal Pierre Elliott Trudeau Intl

Thu 10/9

5:10 p.m.-10:05 p.m.

1 stop7h 55m

Seattle/Tacoma Intl

Tue 15/9

8:59 a.m.-11:50 p.m.

1 stop11h 51m

C$ 502

MontrealSeattle

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

YULSEA

Montreal Pierre Elliott Trudeau Intl

Fri 11/9

12:48 p.m.-10:05 p.m.

1 stop12h 17m

Seattle/Tacoma Intl

Tue 15/9

8:59 a.m.-11:50 p.m.

1 stop11h 51m

C$ 502

MontrealSeattle

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

YULSEA

Montreal Pierre Elliott Trudeau Intl

Mon 8/2

12:45 p.m.-10:05 p.m.

1 stop12h 20m

Seattle/Tacoma Intl

Wed 17/2

11:05 p.m.-12:15 p.m.

1 stop10h 10m

C$ 513

MontrealSeattle

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

YULSEA

Montreal Pierre Elliott Trudeau Intl

Sat 12/9

5:30 p.m.-9:40 a.m.

1 stop19h 10m

Seattle/Tacoma Intl

Mon 14/9

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

1 stop8h 30m

C$ 521

LondonSeattle

YXU London - SEA Seattle/Tacoma Intl

YXUSEA

London

Sun 27/9

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

1 stop15h 35m

Seattle/Tacoma Intl

Sun 4/10

10:30 a.m.-4:45 p.m.

1 stop27h 15m

C$ 535

OttawaSeattle

YOW Ottawa - SEA Seattle/Tacoma Intl

YOWSEA

Ottawa

Sun 27/9

4:15 p.m.-9:40 a.m.

1 stop20h 25m

Seattle/Tacoma Intl

Sat 3/10

10:30 a.m.-12:20 a.m.

2 stops10h 50m

C$ 542

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/8

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$ 351). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 651). 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 13 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 13 August 2026.

The most flights from CAON to SEA are scheduled on a Wednesday (3 on average). You will have fewer flight options on Monday, 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$ 508 and C$ 922 in September.
The cheapest round-trip price found within the last 5 days was C$ 481 on WestJet (3 Sep-6 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 15m. The distance from Region of Ontario to Seattle is about 3306 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$ 152 and C$ 165 on Air Canada and United 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 Hamilton - Seattle/Tacoma Intl or Toronto Region of Waterloo Intl - 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 (90%), Qatar Airways (67%) or Air Canada (53%) 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$ 303. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 524 on average, our data indicates C$ 653 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$ 351). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 651). 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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Vancouver Intl to Seattle flights
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Region of Waterloo Intl to Seattle flights
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Pierre Elliott Trudeau Intl to Seattle flights
Pearson Intl to Portland flights
Vancouver Intl to Spokane flights
Victoria to Seattle flights
Pierre Elliott Trudeau Intl to Portland flights
Toronto Island to Portland flights
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Québec City to Seattle flights
Ottawa to Seattle flights
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Victoria to Portland flights
Calgary to Portland flights
Hamilton to Portland flights
Edmonton to Portland flights
Region of Waterloo Intl to Portland flights
Calgary to Spokane flights
Saskatoon to Seattle flights
Pearson Intl to Spokane flights
Regina to Portland flights
Regina to Seattle flights
Kamloops to Portland flights
London to Seattle flights
Halifax to Seattle flights
Winnipeg to Portland flights
Prince George to Seattle flights
Vancouver Intl to Bellingham flights
Pierre Elliott Trudeau Intl to Spokane flights
Nanaimo to Portland flights
Kelowna to Portland flights
Québec City to Portland flights
Saskatoon to Portland flights
Edmonton to Spokane flights
Ottawa to Portland flights
Fort St. John to Portland flights
Thunder Bay to Portland flights
Sault Ste Marie to Seattle flights
Pearson Intl to Pasco flights
Windsor to Seattle flights
London to Portland flights

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 13 August 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapestC$ 225AverageC$ 839FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Air CanadaCheapestC$ 252AverageC$ 621FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
United AirlinesCheapestC$ 267AverageC$ 657FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Alaska AirlinesCheapestC$ 270AverageC$ 424FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
WestJetCheapestC$ 272AverageC$ 484FlexibilityNo cancel feeOn-time60%
Search WestJet 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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