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$125+ Cheap flights from Ontario to Seattle (SEA)

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 10/20. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
Oct 15 — Oct 221
Wed 10/15
Wed 10/22
1 adult, Economy
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Cheap flight deals from Ontario to Seattle

Keep the following information in mind while searching for Ontario to Seattle flight deals. Data was last updated September 15, 2025.

Round-trip from

$204
(Trip.com)

One-way from

$125
(Trip.com)

Popular in

December

Cheapest in

February

Average price

$396

Good round-trip deal

$312 or less

Good one-way deal

$296 or less
From Ontario to Seattle/Tacoma Intl
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One-way flight from Ontario to Seattle/Tacoma Intl
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High demand for flights, 7% potential price rise
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Cheapest flight prices on average. 1% potential price decrease ($5 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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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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Find flight deals from Ontario to Seattle

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 September 15, 2025.

This Trip.com deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/216:00 amYHM - SEA
1 stop9h 59mWestJet
Fri 10/241:50 pmSEA - YHM
1 stop7h 50mWestJet
Deal found 9/13$204
This Trip.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/206:00 amYHM - SEA
1 stop9h 59mWestJet
Fri 10/241:50 pmSEA - YHM
1 stop7h 50mWestJet
Deal found 9/15$206
This FlightHub deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/156:00 amYHM - SEA
1 stop9h 59mWestJet
Wed 10/221:50 pmSEA - YHM
1 stop7h 50mWestJet
Deal found 9/15$207
This Air Canada deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/712:00 pmYYZ - SEA
1 stop10h 31mAir Canada
Mon 10/202:55 pmSEA - YYZ
1 stop7h 11mAir Canada
Deal found 9/15$228
This FlightHub deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/156:00 amYHM - SEA
1 stop9h 59mWestJet
Thu 10/231:50 pmSEA - YHM
1 stop7h 50mWestJet
Deal found 9/15$229
This FlightHub deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/36:45 amYYZ - SEA
1 stop8h 50mWestJet
Tue 10/72:05 pmSEA - YYZ
2 stops12h 46mWestJet
Deal found 9/15$229
This Kiwi.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/293:35 pmYOW - SEA
1 stop7h 54mWestJet
Thu 10/28:40 amSEA - YOW
2 stops12h 42mWestJet
Deal found 9/15$230
This Trip.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/276:20 amYKF - SEA
1 stop11h 00mWestJet
Sun 11/303:10 pmSEA - YKF
1 stop11h 18mWestJet
Deal found 9/15$230
This Air Canada deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/76:15 amYYZ - SEA
2 stops11h 01mAir Canada
Tue 10/2110:00 amSEA - YYZ
2 stops9h 05mAir Canada
Deal found 9/14$230
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/258:00 amYYZ - SEA
1 stop7h 59mMultiple Airlines
Sat 11/17:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 9/14$231
This Kiwi.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/36:45 amYYZ - SEA
1 stop8h 50mWestJet
Fri 10/101:15 pmSEA - YYZ
1 stop8h 16mWestJet
Deal found 9/15$232
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/36:45 amYYZ - SEA
1 stop8h 50mWestJet
Sun 10/128:40 amSEA - YYZ
1 stop7h 12mWestJet
Deal found 9/14$233

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 2,558,603 searches. Data last updated September 15, 2025.
Use the filters below to find and compare flights from Ontario to Seattle that are best for you.

Fly from

Ontario

Fly to

Seattle

Route

Depart

Return

Price

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Tue 10/21

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

Fri 10/24

1:50 pm-12:40 am

1 stop7h 50m

$204

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Wed 10/15

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

Wed 10/22

1:50 pm-12:40 am

1 stop7h 50m

$204

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Wed 10/15

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

Thu 10/23

1:50 pm-12:40 am

1 stop7h 50m

$229

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 11/27

6:20 am-2:20 pm

1 stop11h 00m

Seattle/Tacoma Intl

Sun 11/30

3:10 pm-5:28 am

1 stop11h 18m

$230

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Mon 11/3

6:40 pm-11:11 am

1 stop19h 31m

Seattle/Tacoma Intl

Fri 11/7

8:15 am-3:58 pm

Nonstop4h 43m

$241

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 10/7

7:00 am-9:34 pm

3 stops17h 34m

Seattle/Tacoma Intl

Tue 10/21

1:57 pm-11:58 pm

1 stop7h 01m

$242

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Thu 10/23

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

Sun 10/26

3:10 pm-5:17 pm

1 stop23h 07m

$242

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Thu 10/16

12:00 pm-7:21 pm

2 stops10h 21m

Seattle/Tacoma Intl

Sat 10/18

8:40 am-12:31 am

2 stops12h 51m

$243

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 10/8

7:30 am-10:17 pm

1 stop17h 47m

Seattle/Tacoma Intl

Mon 10/20

2:55 pm-1:06 am

1 stop7h 11m

$246

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Sat 10/25

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

Sun 11/2

3:10 pm-5:17 pm

1 stop23h 07m

$249

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Showing 1-10 of 60 results
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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 $238). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of $387). 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 September 15, 2025.

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 September 15, 2025.

The most flights from CAON to SEA are scheduled on a Sunday (6 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (4 on average).

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

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?

    Seattle/Tacoma Intl (SEA), located 11.4 mi from the city center, is the airport you fly into when you book flights from Ontario to Seattle.

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

    WestJet, United Airlines, and Air Canada can get you from Region of Ontario to Seattle in just under 9h 59m. Your travel time can differ by up to 3h 29m. Airlines will cover a distance of 2053 mi. Both multi-stop and nonstop flights can be found to your destination and back.

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

    $125 is the cheapest one-way deal found within the past few days, from WestJet. You may also be able to find cheap deals on United Airlines and Air Canada, with prices starting from $153 and $164, respectively.

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

    When deciding which route to take from Region of Ontario to Seattle consider Toronto Pearson Intl - Seattle/Tacoma Intl, Toronto Island - Seattle/Tacoma Intl or Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl as they are the most popular.

  • 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%), Hawaiian Airlines (90%) or Air Tahiti Nui (86%) 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?

    On average you can expect to pay $419 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $147 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $200.

  • 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 $238). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of $387). 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

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Tukwila
Tacoma
Lakewood
Ocean Shores
Lynnwood
Edmonds
Leavenworth
Renton
Lacey
Olympia
Kent
Federal Way
Cle Elum
Puyallup
Chehalis
Kirkland
Issaquah
Aberdeen
Shoreline

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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 6 airlines flying from Ontario to Seattle

Discover the top 6 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 2,558,603 searches. Data last updated September 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$193Average$371FlexibilityNo cancel feeOn-time60%
United AirlinesCheapest$240Average$468FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$246Average$376FlexibilityNo cancel feeOn-time75%
Air CanadaCheapest$247Average$447FlexibilityNo cancel feeOn-time67%
American AirlinesCheapest$277Average$277FlexibilityNo cancel feeOn-time71%
DeltaCheapest$289Average$362FlexibilityNo cancel feeOn-timeN/A

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