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$145+ 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 4/27. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
Apr 30 — May 71
Thu 4/30
Thu 5/7
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 March 31, 2026.

This Kiwi.com deal was found by Cheapflights users on 3/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/71:30 pm
YYZ
-
SEA
1 stop8h 15m
WestJet
Tue 5/1210:30 am
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 3/30$214
This oojo deal was found by Cheapflights users on 3/30. 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 oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/412:00 pm
YYZ
-
SEA
2 stops9h 45m
WestJet
Tue 6/910:30 am
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 3/30$217
This oojo deal was found by Cheapflights users on 3/28. 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 oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/412:00 pm
YYZ
-
SEA
2 stops9h 45m
WestJet
Tue 6/2310:30 am
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 3/28$218
This FlightHub deal was found by Cheapflights users on 3/30. 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.
Sat 5/1612:00 pm
YYZ
-
SEA
1 stop9h 45m
WestJet
Sat 5/237:35 pm
SEA
-
YYZ
1 stop8h 20m
WestJet
Deal found 3/30$220
This FlightHub deal was found by Cheapflights users on 3/28. 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.
Thu 6/412:00 pm
YYZ
-
SEA
2 stops9h 45m
WestJet
Mon 6/87:35 pm
SEA
-
YYZ
1 stop7h 10m
WestJet
Deal found 3/28$221
This Flightnetwork deal was found by Cheapflights users on 3/28. 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/127:45 am
YYZ
-
SEA
2 stops9h 35m
Air Canada
Tue 5/197:20 pm
SEA
-
YYZ
2 stops9h 50m
Air Canada
Deal found 3/28$222
This Justfly.com deal was found by Cheapflights users on 3/28. 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 Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/161:30 pm
YYZ
-
SEA
1 stop8h 15m
WestJet
Fri 5/2910:30 am
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 3/28$223
This Kiwi.com deal was found by Cheapflights users on 3/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/245:00 pm
YYZ
-
SEA
1 stop24h 31m
WestJet
Sat 5/167:35 pm
SEA
-
YYZ
1 stop8h 20m
WestJet
Deal found 3/30$224
This Kiwi.com deal was found by Cheapflights users on 3/31. 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 5/1510:25 pm
YYZ
-
SEA
1 stop14h 15m
WestJet
Tue 5/1910:30 am
SEA
-
YYZ
1 stop7h 45m
WestJet
Deal found 3/31$225
This CheapOair deal was found by Cheapflights users on 3/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/224:55 pm
YYZ
-
SEA
Nonstop5h 28m
Alaska Airlines
Wed 4/297:55 am
SEA
-
YYZ
Nonstop4h 50m
Alaska Airlines
Deal found 3/28$226
This Kiwi.com deal was found by Cheapflights users on 3/29. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/312:00 pm
YYZ
-
SEA
1 stop9h 45m
WestJet
Wed 5/1310:30 am
SEA
-
YYZ
1 stop7h 45m
WestJet
Deal found 3/29$227
This oojo deal was found by Cheapflights users on 3/30. 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 oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/25:20 pm
YYZ
-
SEA
2 stops19h 20m
WestJet
Thu 5/710:30 am
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 3/30$228

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 March 31, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$214
(Kiwi.com)

One-way from

$145
(FlightHub)

Popular in

June

Cheapest in

February

Average price

$333

Good round-trip deal

$383 or less

Good one-way deal

$250 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
Highest demand for flights based on searches. 5% potential increase in price ($18 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($6 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 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 2,558,603 searches. Data last updated March 31, 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

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 4/25

7:00 am-11:27 pm

2 stops19h 27m

Seattle/Tacoma Intl

Sat 5/2

5:05 am-9:32 pm

1 stop13h 27m

$257

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 4/14

5:16 pm-11:27 pm

1 stop9h 11m

Seattle/Tacoma Intl

Sat 4/18

11:59 pm-9:54 am

1 stop6h 55m

$257

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 4/28

10:45 am-11:27 pm

2 stops15h 42m

Seattle/Tacoma Intl

Tue 5/5

2:27 pm-11:59 pm

1 stop6h 32m

$257

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Wed 4/29

6:10 pm-9:40 am

1 stop18h 30m

Seattle/Tacoma Intl

Tue 5/5

7:35 pm-5:15 pm

1 stop18h 40m

$259

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Tue 5/12

6:10 pm-6:45 pm

1 stop27h 35m

Seattle/Tacoma Intl

Tue 5/19

7:35 pm-5:15 pm

1 stop18h 40m

$260

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Tue 4/28

6:10 pm-6:45 pm

1 stop27h 35m

Seattle/Tacoma Intl

Sat 5/2

10:30 am-5:15 pm

1 stop27h 45m

$268

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 5/9

6:10 am-2:53 pm

1 stop11h 43m

Seattle/Tacoma Intl

Sun 5/17

5:30 am-3:14 pm

1 stop6h 44m

$275

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 4/29

12:22 pm-8:42 pm

1 stop11h 20m

Seattle/Tacoma Intl

Fri 5/1

11:59 pm-11:32 am

1 stop8h 33m

$276
Quickest round-trip

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 5/5

4:55 pm-7:23 pm

Nonstop5h 28m

Seattle/Tacoma Intl

Sat 5/9

7:55 am-3:45 pm

Nonstop4h 50m

$291

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Thu 4/23

2:15 pm-9:50 pm

1 stop10h 35m

Seattle/Tacoma Intl

Wed 4/29

11:14 pm-1:24 pm

1 stop11h 10m

$297

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/29

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 $131). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of $236). 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 March 31, 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 March 31, 2026.

The most flights from CAON to SEA are scheduled on a Monday (6 on average). You will have fewer flight options on Friday, 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?

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?

    United Airlines, WestJet, and Air Canada can get you from Region of Ontario to Seattle in just under 18h 10m. Your travel time can differ by up to 1h 17m. Airlines will cover a distance of 2065 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?

    $100 is the cheapest one-way deal found within the past few days, from WestJet. You may also be able to find cheap deals on Air Canada and Alaska Airlines, with prices starting from $121 and $128, 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 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 Air Tahiti Nui (80%), Qatar Airways (79%) or Alaska Airlines (75%) 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 $391 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $184 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $228.

  • 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 $131). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of $236). 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
Tacoma
Ocean Shores
Olympia
Kent
Lynnwood
Lacey
Edmonds
Leavenworth
Snoqualmie
Tukwila
Renton
Puyallup
Kirkland
Ellensburg
Fife
Lakewood
Issaquah
Shoreline
Aberdeen

Browse thousands of different options on Cheapflights for your next trip

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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 March 31, 2026.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$193Average$363FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$202Average$391FlexibilityNo cancel feeOn-time75%
Air CanadaCheapest$213Average$425FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$238Average$424FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$277Average$277FlexibilityNo cancel feeOn-time71%
DeltaCheapest$289Average$364FlexibilityNo cancel feeOn-timeN/A

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