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Cheap flights from Ontario to Seattle from C$ 263

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 10/10. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
28 Jul — 4 Aug1
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 28 June 2026.

Wed 28/107:45 a.m.
YYZ
-
SEA
1 stop9h 35m
WestJet
Sat 31/103:20 p.m.
SEA
-
YYZ
2 stops11h 38m
WestJet
Deal found 25/6C$ 387
Wed 4/116:30 a.m.
YYZ
-
SEA
1 stop9h 50m
WestJet
Wed 18/113:10 p.m.
SEA
-
YYZ
2 stops10h 48m
WestJet
Deal found 25/6C$ 393
Wed 21/1012:00 p.m.
YYZ
-
SEA
1 stop9h 45m
WestJet
Mon 26/103:10 p.m.
SEA
-
YYZ
2 stops11h 48m
WestJet
Deal found 25/6C$ 410
Wed 25/116:30 a.m.
YYZ
-
SEA
1 stop9h 50m
WestJet
Sun 29/113:10 p.m.
SEA
-
YYZ
2 stops28h 33m
WestJet
Deal found 26/6C$ 412
Thu 1/1012:00 p.m.
YYZ
-
SEA
1 stop9h 45m
WestJet
Wed 11/113:10 p.m.
SEA
-
YYZ
2 stops10h 48m
WestJet
Deal found 27/6C$ 416
Sat 3/101:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Sat 10/107:35 p.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Deal found 27/6C$ 420
Wed 14/101:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Wed 18/113:10 p.m.
SEA
-
YYZ
2 stops10h 48m
WestJet
Deal found 27/6C$ 422
Sat 24/1012:40 p.m.
YYZ
-
SEA
2 stops9h 05m
WestJet
Mon 26/103:10 p.m.
SEA
-
YYZ
2 stops11h 48m
WestJet
Deal found 27/6C$ 423
Thu 1/101:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Tue 6/107:35 p.m.
SEA
-
YYZ
1 stop8h 20m
WestJet
Deal found 26/6C$ 424
Wed 21/101:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Sat 24/1010:30 a.m.
SEA
-
YYZ
1 stop9h 15m
WestJet
Deal found 25/6C$ 429
Fri 11/912:00 p.m.
YYZ
-
SEA
1 stop9h 45m
WestJet
Mon 21/97:35 p.m.
SEA
-
YYZ
1 stop8h 20m
WestJet
Deal found 24/6C$ 430
Thu 8/106:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Thu 22/107:35 p.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Deal found 23/6C$ 463

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 28 June 2026.

Round-trip from

C$ 387

One-way from

C$ 263

Popular in

June

Cheapest in

February

Average price

C$ 711

Good round-trip deal

C$ 739 or less

Good one-way deal

C$ 416 or less
WestJet
  • WestJet
  • 28/10-31/10
  • 3 total stops
  • 21h 13m total
  • Ontario to Seattle
Search Deals
WestJet
  • WestJet
  • 10/10
  • 1 total stop
  • 9h 45m 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$ 28 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 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 28 June 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

LondonSeattle

YXU - SEA

YXUSEA

London

Wed 9/9

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

1 stop15h 35m

Seattle/Tacoma Intl

Thu 10/9

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

1 stop6h 45m

C$ 492

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Thu 3/9

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

1 stop18h 30m

Seattle/Tacoma Intl

Mon 7/9

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

1 stop7h 15m

C$ 518

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 10/9

8:40 p.m.-9:40 a.m.

1 stop16h 00m

Seattle/Tacoma Intl

Sun 13/9

7:35 p.m.-7:50 p.m.

1 stop21h 15m

C$ 519

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 25/9

8:40 p.m.-9:40 a.m.

1 stop16h 00m

Seattle/Tacoma Intl

Mon 28/9

7:35 p.m.-7:50 p.m.

1 stop21h 15m

C$ 524

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Wed 15/7

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

1 stop18h 30m

Seattle/Tacoma Intl

Thu 23/7

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

1 stop7h 15m

C$ 529

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 3/9

8:40 p.m.-6:45 p.m.

1 stop25h 05m

Seattle/Tacoma Intl

Tue 8/9

7:00 a.m.-7:50 p.m.

1 stop9h 50m

C$ 534

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Wed 28/10

6:10 p.m.-2:20 p.m.

1 stop23h 10m

Seattle/Tacoma Intl

Sat 31/10

3:20 p.m.-5:17 p.m.

1 stop22h 57m

C$ 536

OttawaSeattle

YOW - SEA

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$ 538

MontrealSeattle

YUL - SEA

YULSEA

Montreal Pierre Elliott Trudeau Intl

Wed 23/9

9:15 a.m.-3:43 p.m.

1 stop9h 28m

Seattle/Tacoma Intl

Sun 27/9

11:13 p.m.-10:40 a.m.

1 stop8h 27m

C$ 546

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 1/9

11:00 a.m.-5:42 p.m.

2 stops9h 42m

Seattle/Tacoma Intl

Wed 9/9

11:03 a.m.-9:32 p.m.

1 stop7h 29m

C$ 554

Flights are sorted by cheapest round-trip flights first.

Deals found on 25/6

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, January is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 89). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 1,097). 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 28 June 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 28 June 2026.

The most flights from CAON to SEA are scheduled on a Tuesday (4 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (2 on average).

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

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 9h 28m. 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$ 124. Users have also found prices from C$ 155 and C$ 168 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 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 Hawaiian Airlines (100%), Alaska Airlines (95%) or Qatar Airways (67%) 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$ 339. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 461 on average, our data indicates C$ 812 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, January is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 89). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 1,097). 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
Tukwila
Olympia
Marysville
Federal Way
Kirkland

Browse thousands of different options on Cheapflights for your next trip

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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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Winnipeg to Portland flights
Edmonton to Portland flights
Region of Waterloo Intl to Portland flights
Pearson Intl to Spokane flights
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Victoria to Portland flights
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London to Seattle flights
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Prince George to Seattle flights
Edmonton to Spokane flights
Saskatoon to Portland flights
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Pearson Intl to Pasco flights
Nanaimo to Portland flights
Thunder Bay to Portland flights
Kamloops to Portland flights
Calgary to Spokane flights
Québec City to Portland flights
Regina to Portland flights
St John to Portland flights
Pierre Elliott Trudeau Intl to Spokane flights
London to Portland flights
Vancouver Intl to Bellingham flights
Windsor to Seattle flights
Campbell River to Seattle 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 28 June 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapestC$ 230AverageC$ 517FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
United AirlinesCheapestC$ 258AverageC$ 675FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 274AverageC$ 623FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
Alaska AirlinesCheapestC$ 277AverageC$ 436FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
WestJetCheapestC$ 278AverageC$ 467FlexibilityNo cancel feeOn-time60%
Search WestJet flights

Fly with Cheapflights

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

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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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