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Cheap flights from Ontario to Seattle from C$ 238

YYZ — SEA
22 Sep — 29 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

Sat 12/912:25 p.m. -
2 stops9h 20m
Wed 16/97:35 p.m. -
1 stop7h 00m
Deal found 21/8C$ 304
Sat 19/912:25 p.m. -
2 stops9h 20m
Sat 26/97:35 p.m. -
1 stop7h 00m
Deal found 20/8C$ 362
Wed 23/94:15 p.m. -
1 stop20h 25m
Wed 30/97:35 p.m. -
1 stop7h 00m
Deal found 21/8C$ 366
Fri 4/91:20 p.m. -
1 stop8h 25m
Tue 8/97:35 p.m. -
1 stop7h 00m
Deal found 22/8C$ 403
Fri 25/98:15 p.m. -
1 stop16h 25m
Thu 1/107:35 p.m. -
1 stop7h 00m
Deal found 21/8C$ 406
Wed 16/96:45 a.m. -
2 stops15h 00m
Wed 23/97:35 p.m. -
1 stop8h 30m
Deal found 18/8C$ 410
Thu 24/96:45 a.m. -
2 stops15h 00m
Mon 28/97:35 p.m. -
1 stop8h 30m
Deal found 19/8C$ 412
Wed 30/96:55 a.m. -
2 stops14h 50m
Sun 4/107:35 p.m. -
1 stop7h 00m
Deal found 21/8C$ 413
Wed 23/96:45 a.m. -
2 stops15h 00m
Mon 28/97:35 p.m. -
1 stop8h 30m
Deal found 21/8C$ 414
Tue 15/96:45 a.m. -
2 stops15h 00m
Tue 22/97:35 p.m. -
1 stop8h 30m
Deal found 19/8C$ 421
Fri 18/98:00 p.m. -
1 stop16h 40m
Mon 28/97:35 p.m. -
1 stop8h 30m
Deal found 19/8C$ 428
Fri 4/96:45 a.m. -
2 stops15h 00m
Fri 11/97:35 p.m. -
1 stop8h 30m
Deal found 23/8C$ 431

Find flight deals from Ontario to Seattle

Round-trip from

C$ 304

One-way from

C$ 238

Popular in

June

Cheapest in

February

Average price

C$ 621

Good round-trip deal

C$ 649 or less

Good one-way deal

C$ 347 or less
WestJet
  • WestJet
  • 12/9-16/9
  • 3 total stops
  • 16h 20m total
  • Ontario to Seattle
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WestJet
  • WestJet
  • 29/9
  • 1 total stop
  • 8h 25m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 13% potential increase in price (C$ 108 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 20 potential savings vs. average RT price).
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Average for round-trip flights in August 2026
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Price to beat on a round-trip flight from Ontario to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from Ontario to Seattle/Tacoma Intl.
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Cheapflights Fare Finder

 
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

OttawaSeattle

YOW Ottawa - SEA Seattle/Tacoma Intl

YOWSEA

Ottawa

Fri 25/9

8:15 p.m.-9:40 a.m.

1 stop16h 25m

Seattle/Tacoma Intl

Thu 1/10

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

2 stops10h 50m

C$ 421

OttawaSeattle

YOW Ottawa - SEA Seattle/Tacoma Intl

YOWSEA

Ottawa

Sat 12/9

1:20 p.m.-6:45 p.m.

1 stop8h 25m

Seattle/Tacoma Intl

Wed 16/9

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

1 stop20h 45m

C$ 456

OttawaSeattle

YOW Ottawa - SEA Seattle/Tacoma Intl

YOWSEA

Ottawa

Sun 4/10

12:25 p.m.-6:45 p.m.

2 stops9h 20m

Seattle/Tacoma Intl

Sun 11/10

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

1 stop7h 00m

C$ 458

TorontoSeattle

YKF Toronto Region of Waterloo Intl - SEA Seattle/Tacoma Intl

YKFSEA

Toronto Region of Waterloo Intl

Wed 16/9

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

1 stop16h 00m

Seattle/Tacoma Intl

Wed 30/9

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

1 stop21h 15m

C$ 475

TorontoSeattle

YKF Toronto Region of Waterloo Intl - SEA Seattle/Tacoma Intl

YKFSEA

Toronto Region of Waterloo Intl

Thu 24/9

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$ 475

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Fri 11/9

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

1 stop27h 35m

Seattle/Tacoma Intl

Wed 16/9

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

1 stop18h 40m

C$ 476

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Thu 17/9

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

1 stop18h 30m

Seattle/Tacoma Intl

Thu 24/9

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

1 stop18h 40m

C$ 476

HamiltonSeattle

YHM Hamilton - SEA Seattle/Tacoma Intl

YHMSEA

Hamilton

Fri 11/9

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

1 stop18h 30m

Seattle/Tacoma Intl

Sat 12/9

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

1 stop18h 40m

C$ 476

TorontoSeattle

YKF Toronto Region of Waterloo Intl - SEA Seattle/Tacoma Intl

YKFSEA

Toronto Region of Waterloo Intl

Wed 30/9

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

1 stop16h 00m

Seattle/Tacoma Intl

Sun 11/10

8:02 a.m.-7:50 p.m.

1 stop8h 48m

C$ 552

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

Wed 30/9

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

1 stop11h 51m

C$ 557

Flights are sorted by cheapest round-trip flights first.

Deals found on 20/8

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

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$ 344). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of C$ 646). 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?

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

The most flights from CAON to SEA are scheduled on a Saturday (4 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$ 496 and C$ 822 in November.
The cheapest round-trip price found within the last 5 days was C$ 469 on WestJet (13 Nov-25 Nov).

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

  • 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 30m. 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$ 121. Users have also found prices from C$ 163 and C$ 168 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 Hamilton - Seattle/Tacoma Intl or Montreal Pierre Elliott Trudeau 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 (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$ 300. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 504 on average, our data indicates C$ 608 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$ 344). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of C$ 646). 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

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Ontario to Seattle

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Top 5 airlines flying from Ontario to Seattle

AirlineCheapestAverageFlexibilityOn-time
DeltaCheapestC$ 223AverageC$ 830FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Air CanadaCheapestC$ 249AverageC$ 618FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
United AirlinesCheapestC$ 264AverageC$ 653FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
WestJetCheapestC$ 267AverageC$ 483FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 267AverageC$ 422FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights

Fly with Cheapflights

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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