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$148+ 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 1/28. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
Jan 13 — Jan 201
Tue 1/13
Tue 1/20
1 adult, Economy
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Cheap 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 December 14, 2025.

This SmartFares deal was found by Cheapflights users on 12/11. 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 SmartFares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/224:45 pmYYZ - SEA
Nonstop5h 26mAlaska Airlines
Thu 1/157:55 amSEA - YYZ
Nonstop4h 40mAlaska Airlines
Deal found 12/11$433
This FlightHub deal was found by Cheapflights users on 12/14. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/261:30 pmYYZ - SEA
1 stop10h 16mMultiple Airlines
Wed 1/77:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 12/14$443
This Kiwi.com deal was found by Cheapflights users on 12/13. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/147:45 amYYZ - SEA
1 stop9h 35mWestJet
Sat 1/1711:55 amSEA - YYZ
2 stops8h 44mWestJet
Deal found 12/13$445
This United Airlines deal was found by Cheapflights users on 12/12. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/266:10 amYYZ - SEA
1 stop19h 42mUnited Airlines
Wed 1/72:10 pmSEA - YYZ
1 stop6h 49mUnited Airlines
Deal found 12/12$458
This Kiwi.com deal was found by Cheapflights users on 12/13. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/148:20 pmYYZ - SEA
2 stops18h 33mMultiple Airlines
Sat 1/177:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 12/13$462
This Kiwi.com deal was found by Cheapflights users on 12/11. 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 12/221:30 pmYYZ - SEA
1 stop10h 16mMultiple Airlines
Thu 1/157:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 12/11$465
This FlightHub deal was found by Cheapflights users on 12/12. 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.
Sun 12/2810:15 pmYYZ - SEA
1 stop12h 05mMultiple Airlines
Sat 1/107:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 12/12$466
This Trip.com deal was found by Cheapflights users on 12/12. 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.
Sun 12/2810:15 pmYYZ - SEA
1 stop12h 05mMultiple Airlines
Thu 1/157:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 12/12$468
This oojo deal was found by Cheapflights users on 12/12. 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 oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/136:30 pmYYZ - SEA
1 stop22h 50mWestJet
Fri 3/133:10 pmSEA - YYZ
2 stops11h 48mWestJet
Deal found 12/12$474
This American Airlines deal was found by Cheapflights users on 12/11. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/224:06 pmYYZ - SEA
1 stop8h 58mAmerican Airlines
Thu 1/1510:50 amSEA - YYZ
1 stop8h 54mAmerican Airlines
Deal found 12/11$491
This FlightHub deal was found by Cheapflights users on 12/13. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/206:00 amYOW - SEA
2 stops13h 45mWestJet
Sat 1/1711:55 amSEA - YOW
2 stops9h 45mWestJet
Deal found 12/13$582
This United Airlines deal was found by Cheapflights users on 12/13. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/205:09 pmYOW - SEA
1 stop8h 38mUnited Airlines
Sat 1/175:00 amSEA - YOW
2 stops15h 54mUnited Airlines
Deal found 12/13$584

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 December 14, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$199
(SmartFares)

One-way from

$148
(Trip.com)

Popular in

December

Cheapest in

February

Average price

$449

Good round-trip deal

$392 or less

Good one-way deal

$163 or less
Provider with most accurate pricing for Toronto (YTO)-Seattle/Tacoma Intl flight deals.
Search Deals
Provider most trusted by Cheapflights users for Toronto (YTO)-Seattle/Tacoma Intl flights.
Search Deals
From Ontario to Seattle/Tacoma Intl
Search Deals
One-way flight from Ontario to Seattle/Tacoma Intl
Search Deals
High demand for flights, 0% potential price rise
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
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 2,558,603 searches. Data last updated December 14, 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

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 2/27

4:45 pm-7:18 pm

Nonstop5h 33m

Seattle/Tacoma Intl

Mon 3/2

7:55 am-3:35 pm

Nonstop4h 40m

$227

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Mon 2/9

4:45 pm-7:17 pm

Nonstop5h 32m

Seattle/Tacoma Intl

Thu 2/19

7:55 am-3:35 pm

Nonstop4h 40m

$227

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 2/9

6:20 am-2:19 pm

1 stop10h 59m

Seattle/Tacoma Intl

Wed 2/11

3:10 pm-5:29 am

1 stop11h 19m

$231

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Thu 2/26

4:45 pm-7:18 pm

Nonstop5h 33m

Seattle/Tacoma Intl

Mon 3/2

7:55 am-3:35 pm

Nonstop4h 40m

$239

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

Wed 4/8

5:40 am-2:19 pm

2 stops11h 39m

Seattle/Tacoma Intl

Tue 4/14

3:10 pm-4:53 pm

1 stop22h 43m

$240

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 1/10

11:00 am-6:26 pm

2 stops10h 26m

Seattle/Tacoma Intl

Sat 1/17

5:00 am-6:57 pm

2 stops10h 57m

$243

TorontoSeattle

YTZ - SEA

YTZSEA

Toronto Island

Sat 1/17

3:30 pm-9:31 am

2 stops21h 01m

Seattle/Tacoma Intl

Wed 1/21

8:00 pm-9:42 am

2 stops10h 42m

$247

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 1/13

3:30 pm-12:59 am

2 stops12h 29m

Seattle/Tacoma Intl

Sun 1/18

8:10 am-11:46 pm

1 stop12h 36m

$251

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Mon 1/12

2:45 pm-8:57 pm

1 stop9h 12m

Seattle/Tacoma Intl

Wed 1/14

7:00 am-9:21 pm

1 stop11h 21m

$251

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 1/13

4:10 pm-9:15 pm

1 stop8h 05m

Seattle/Tacoma Intl

Fri 2/6

3:30 pm-9:58 am

2 stops15h 28m

$251

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/14

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, December is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $133). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of $249). 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 December 14, 2025.

When flying from Region of Ontario to Seattle, the time of day you fly usually plays a role in the price. Save by searching for a flight in the afternoon, which can drop the price by up to 6% versus a flight at noon.

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 December 14, 2025.

The most flights from CAON to SEA are scheduled on a Sunday (7 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (2 on average).

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?

    Alaska Airlines, WestJet, and United Airlines can get you from Region of Ontario to Seattle in just under 5h 33m. Your travel time can differ by up to 5h 26m. Airlines will cover a distance of 2054 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?

    $116 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 $136 and $144, 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, Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl or Hamilton - 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 Hawaiian Airlines (84%), Air Tahiti Nui (84%) or Qatar Airways (78%) 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 $338 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $125 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $209.

  • 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, December is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $133). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of $249). 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
Tacoma
SeaTac
Lakewood
Ocean Shores
Olympia
Edmonds
Lynnwood
Renton
Puyallup
Kirkland
Kent
Tukwila
Cle Elum
Marysville
Leavenworth
Fife
Aberdeen
Shoreline
Centralia
Federal Way

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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 December 14, 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$193Average$379FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$225Average$401FlexibilityNo cancel feeOn-time75%
Air CanadaCheapest$238Average$452FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$240Average$442FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$277Average$277FlexibilityNo cancel feeOn-time71%
DeltaCheapest$289Average$371FlexibilityNo cancel feeOn-timeN/A

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