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$151+ 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 12/10. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
Nov 29 — Dec 61
Sat 11/29
Sat 12/6
1 adult, Economy
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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 October 30, 2025.

This FlightHub deal was found by Cheapflights users on 10/28. 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.
Tue 11/257:45 amYYZ - SEA
1 stop9h 35mWestJet
Wed 12/33:15 pmSEA - YYZ
2 stops11h 43mWestJet
Deal found 10/28$211
This Trip.com deal was found by Cheapflights users on 10/29. 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 11/257:45 amYYZ - SEA
1 stop9h 35mWestJet
Sat 11/293:20 pmSEA - YYZ
2 stops11h 38mWestJet
Deal found 10/29$213
This FlightHub deal was found by Cheapflights users on 10/28. 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 12/37:45 amYYZ - SEA
1 stop9h 50mWestJet
Fri 12/123:10 pmSEA - YYZ
2 stops11h 48mWestJet
Deal found 10/28$218
This FlightHub deal was found by Cheapflights users on 10/29. 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.
Tue 11/257:45 amYYZ - SEA
1 stop9h 35mWestJet
Fri 11/283:10 pmSEA - YYZ
2 stops11h 48mWestJet
Deal found 10/29$219
This FlightHub deal was found by Cheapflights users on 10/30. 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.
Tue 12/27:45 amYYZ - SEA
1 stop9h 35mWestJet
Sun 12/73:10 pmSEA - YYZ
2 stops11h 48mWestJet
Deal found 10/30$221
This KAYAK deal was found by Cheapflights users on 10/29. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/264:45 pmYYZ - SEA
Nonstop5h 32mAlaska Airlines
Wed 12/37:55 amSEA - YYZ
Nonstop4h 40mAlaska Airlines
Deal found 10/29$223
This Kiwi.com deal was found by Cheapflights users on 10/28. 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 11/237:45 amYYZ - SEA
1 stop9h 35mWestJet
Sun 12/711:55 amSEA - YYZ
2 stops8h 44mWestJet
Deal found 10/28$227
This Trip.com deal was found by Cheapflights users on 10/28. 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 12/87:45 amYYZ - SEA
1 stop9h 35mWestJet
Fri 12/123:10 pmSEA - YYZ
2 stops11h 48mWestJet
Deal found 10/28$229
This Trip.com deal was found by Cheapflights users on 10/28. 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 11/257:45 amYYZ - SEA
1 stop9h 35mMultiple Airlines
Tue 12/27:55 amSEA - YYZ
Nonstop4h 40mMultiple Airlines
Deal found 10/28$230
This FlightHub deal was found by Cheapflights users on 10/29. 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 11/218:45 pmYYZ - SEA
1 stop16h 37mWestJet
Sun 12/73:10 pmSEA - YYZ
2 stops11h 48mWestJet
Deal found 10/29$231
This Kiwi.com deal was found by Cheapflights users on 10/28. 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.
Tue 11/257:45 amYYZ - SEA
1 stop9h 35mWestJet
Sun 12/711:55 amSEA - YYZ
2 stops8h 44mWestJet
Deal found 10/28$232
This Kiwi.com deal was found by Cheapflights users on 10/28. 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 11/237:45 amYYZ - SEA
1 stop9h 35mWestJet
Wed 12/33:15 pmSEA - YYZ
2 stops11h 43mWestJet
Deal found 10/28$233

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 October 30, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$213
(Trip.com)

One-way from

$151
(Yatra.com)

Popular in

December

Cheapest in

February

Average price

$330

Good round-trip deal

$299 or less

Good one-way deal

$198 or less
Provider with most accurate pricing for Toronto (YTO)-Seattle/Tacoma Intl flight deals.
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Provider most trusted by Cheapflights users for Toronto (YTO)-Seattle/Tacoma Intl flights.
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From Ontario to Seattle/Tacoma Intl
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One-way flight from Ontario to Seattle/Tacoma Intl
Search Deals
High demand for flights, 3% potential price rise
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in October 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.
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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 October 30, 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

Sat 11/22

4:45 pm-7:17 pm

Nonstop5h 32m

Seattle/Tacoma Intl

Tue 11/25

7:57 am-3:35 pm

Nonstop4h 38m

$241

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

Tue 4/14

5:50 pm-10:08 pm

1 stop7h 18m

Seattle/Tacoma Intl

Wed 4/15

8:00 pm-6:43 am

1 stop7h 43m

$243

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 11/25

4:45 pm-7:17 pm

Nonstop5h 32m

Seattle/Tacoma Intl

Sun 12/7

7:55 am-3:35 pm

Nonstop4h 40m

$249

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 11/26

5:55 pm-12:59 am

1 stop10h 04m

Seattle/Tacoma Intl

Tue 12/2

8:10 am-3:53 pm

Nonstop4h 43m

$254

LondonSeattle

YXU - SEA

YXUSEA

London

Sat 2/7

5:40 pm-10:16 pm

1 stop7h 36m

Seattle/Tacoma Intl

Sun 2/22

8:10 am-9:21 pm

1 stop10h 11m

$256

MontrealSeattle

YUL - SEA

YULSEA

Montreal Pierre Elliott Trudeau Intl

Wed 1/14

7:30 pm-2:20 pm

1 stop21h 50m

Seattle/Tacoma Intl

Wed 1/21

3:10 pm-7:05 am

1 stop12h 55m

$259

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 11/26

5:55 pm-12:59 am

1 stop10h 04m

Seattle/Tacoma Intl

Wed 12/3

3:25 pm-7:30 am

1 stop13h 05m

$266

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Mon 11/24

6:05 am-10:46 am

1 stop7h 41m

Seattle/Tacoma Intl

Thu 12/4

1:47 pm-11:27 pm

1 stop6h 40m

$271

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 11/18

3:38 pm-10:23 pm

1 stop9h 45m

Seattle/Tacoma Intl

Sun 11/23

11:10 pm-11:24 am

1 stop9h 14m

$271

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Thu 11/27

7:40 am-6:09 pm

1 stop13h 29m

Seattle/Tacoma Intl

Fri 12/5

11:15 pm-11:25 am

1 stop9h 10m

$271

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/29

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, May is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $92). 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 October 30, 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 5% versus a flight at noon.

What is the cheapest day to fly from Region of Ontario to Seattle?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Seattle. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Region of Ontario to Seattle flight should consider departing on Tuesday mornings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

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?

    Alaska Airlines, Air Canada, and WestJet can get you from Region of Ontario to Seattle in just under 5h 32m. Your travel time can differ by up to 16h 18m. 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?

    $151 is the cheapest one-way deal found within the past few days, from Air Canada. You may also be able to find cheap deals on Alaska Airlines and WestJet, with prices starting from $154 and $158, 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 Alaska Airlines (95%), Air Tahiti Nui (94%) or Hawaiian Airlines (90%) 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 $624 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $153 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $218.

  • 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, May is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $92). 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
SeaTac
Tukwila
Tacoma
Lakewood
Olympia
Ocean Shores
Lynnwood
Edmonds
Leavenworth
Renton
Kirkland
Lacey
Kent
Federal Way
Cle Elum
Marysville
Puyallup
Chehalis
Fife
Issaquah

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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 October 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$192Average$380FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$225Average$416FlexibilityNo cancel feeOn-time75%
Air CanadaCheapest$238Average$462FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$243Average$450FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$277Average$277FlexibilityNo cancel feeOn-time71%
DeltaCheapest$289Average$364FlexibilityNo cancel feeOn-timeN/A

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