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$152+ 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 6/30. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
mars 30 — avr. 61
dim. 3/30
dim. 4/6
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 mars 25, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$243
(oojo)

One-way from

$152
(Trip.com)

Popular in

May

Cheapest in

February

Average price

$357

Good round-trip deal

$318 or less

Good one-way deal

$237 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
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Highest demand for flights based on searches. 13% potential increase in price ($59 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($8 potential savings vs. average RT price).
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Average for round-trip flights in March 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 mars 25, 2025.

This oojo deal was found by Cheapflights users on 3/24. 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.
mar. 7/156:00 amYKF - SEA
1 stop9h 58mWestJet
mar. 7/297:05 amSEA - YKF
1 stop8h 51mWestJet
Deal found 3/24$243
This Kiwi.com deal was found by Cheapflights users on 3/24. 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.
mar. 4/298:00 amYYZ - SEA
1 stop7h 58mMultiple Airlines
mer. 4/3012:30 pmSEA - YYZ
2 stops15h 22mMultiple Airlines
Deal found 3/24$246
This Trip.com deal was found by Cheapflights users on 3/24. 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.
mar. 4/296:00 amYHM - SEA
1 stop9h 58mWestJet
mer. 4/301:50 pmSEA - YHM
1 stop7h 51mWestJet
Deal found 3/24$251
This Trip.com deal was found by Cheapflights users on 3/24. 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.
mar. 4/157:55 amYYZ - SEA
1 stop9h 26mWestJet
mer. 4/233:15 pmSEA - YYZ
2 stops11h 43mWestJet
Deal found 3/24$256
This Trip.com deal was found by Cheapflights users on 3/24. 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.
mar. 4/296:00 amYKF - SEA
1 stop9h 58mMultiple Airlines
mer. 4/301:50 pmSEA - YKF
1 stop12h 25mMultiple Airlines
Deal found 3/24$260
This oojo deal was found by Cheapflights users on 3/23. 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.
mar. 7/156:00 amYOW - SEA
1 stop9h 58mWestJet
mar. 7/222:05 pmSEA - YOW
1 stop7h 36mWestJet
Deal found 3/23$265
This Booking.com deal was found by Cheapflights users on 3/24. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
ven. 5/912:25 pmYTZ - SEA
1 stop10h 12mAir Canada
dim. 5/187:20 amSEA - YTZ
1 stop9h 30mAir Canada
Deal found 3/24$280
This Trip.com deal was found by Cheapflights users on 3/24. 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.
ven. 8/156:00 amYXU - SEA
1 stop15h 38mWestJet
ven. 8/227:05 amSEA - YXU
1 stop9h 04mWestJet
Deal found 3/24$281
This Air Canada deal was found by Cheapflights users on 3/23. 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.
jeu. 5/112:00 pmYYZ - SEA
1 stop10h 37mAir Canada
jeu. 5/82:55 pmSEA - YYZ
1 stop7h 14mAir Canada
Deal found 3/23$289
This Mytrip deal was found by Cheapflights users on 3/24. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 4/296:00 amYHM - SEA
2 stops32h 35mMultiple Airlines
mer. 4/301:50 pmSEA - YHM
1 stop7h 51mMultiple Airlines
Deal found 3/24$298
This Alaska Airlines deal was found by Cheapflights users on 3/24. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 4/154:45 pmYYZ - SEA
Nonstop5h 20mAlaska Airlines
sam. 4/197:20 amSEA - YYZ
Nonstop4h 40mAlaska Airlines
Deal found 3/24$299
This United Airlines deal was found by Cheapflights users on 3/24. 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.
mar. 4/292:45 pmYYZ - SEA
1 stop10h 58mUnited Airlines
mer. 4/306:00 amSEA - YYZ
Nonstop4h 57mUnited Airlines
Deal found 3/24$309

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 mars 25, 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

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

mar. 7/15

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

mar. 7/29

7:05 am-6:56 pm

1 stop8h 51m

$243

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

mar. 4/29

8:00 am-12:58 pm

1 stop7h 58m

Seattle/Tacoma Intl

mer. 4/30

12:30 pm-6:52 am

2 stops15h 22m

$246

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

mar. 4/29

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

mer. 4/30

1:50 pm-12:41 am

1 stop7h 51m

$251

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

mar. 4/15

7:55 am-2:21 pm

1 stop9h 26m

Seattle/Tacoma Intl

mer. 4/23

3:15 pm-5:58 am

2 stops11h 43m

$256

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

mar. 4/29

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

mer. 4/30

1:50 pm-5:15 am

1 stop12h 25m

$260

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

mar. 7/15

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

mar. 7/22

2:05 pm-12:41 am

1 stop7h 36m

$265

TorontoSeattle

YTZ - SEA

YTZSEA

Toronto Island

ven. 5/9

12:25 pm-7:37 pm

1 stop10h 12m

Seattle/Tacoma Intl

dim. 5/18

7:20 am-7:50 pm

1 stop9h 30m

$280

LondonSeattle

YXU - SEA

YXUSEA

London

ven. 8/15

6:00 am-6:38 pm

1 stop15h 38m

Seattle/Tacoma Intl

ven. 8/22

7:05 am-7:09 pm

1 stop9h 04m

$281

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

jeu. 5/1

12:00 pm-7:37 pm

1 stop10h 37m

Seattle/Tacoma Intl

jeu. 5/8

2:55 pm-1:09 am

1 stop7h 14m

$289

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

mar. 4/29

6:00 am-11:35 am

2 stops32h 35m

Seattle/Tacoma Intl

mer. 4/30

1:50 pm-12:41 am

1 stop7h 51m

$298

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/23

Showing 1-10 of 55 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 July is currently the most expensive (average of $411). 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 mars 25, 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 mars 25, 2025.

The most flights from CAON to SEA are scheduled on a Monday (5 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (2 on average).

Rainfall in Seattle by month

Plan your trip to Seattle by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Seattle ranges from 0.7 - 6.6 inches per month. November is typically the wettest month, when rainfall can reach 6.6 in. July is typically the driest time to visit Seattle when rainfall is around 0.7 in.

Temperature in Seattle by month

Plan your trip to Seattle by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Seattle, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 66.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 41.0 F).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Seattle. Reviews last updated mars 25, 2025.
Read reviews from past customers who have flown Alaska Airlines, Delta and Porter Airlines from Ontario to Seattle. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,782 reviews

Boarding

8.2

Overall

8.0

Crew

8.5

Food

7.1

Comfort

7.9

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very good
9,782 reviews
Alaska Airlines
8.0
Very good
9,782 reviews

Boarding

8.2

Overall

8.0

Crew

8.5

Food

7.1

Comfort

7.9

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very good
7,890 reviews
Alaska Airlines
8.0
Very good
9,782 reviews

Boarding

8.2

Overall

8.0

Crew

8.5

Food

7.1

Comfort

7.9

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Porter Airlines
7.9
Good
275 reviews
Alaska Airlines
8.0
Very good
9,782 reviews

Boarding

8.2

Overall

8.0

Crew

8.5

Food

7.1

Comfort

7.9

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.9
Good
2,330 reviews
Alaska Airlines
8.0
Very good
9,782 reviews

Boarding

8.2

Overall

8.0

Crew

8.5

Food

7.1

Comfort

7.9

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,605 reviews
Alaska Airlines
8.0
Very good
9,782 reviews

Boarding

8.2

Overall

8.0

Crew

8.5

Food

7.1

Comfort

7.9

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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.

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

    $152 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 $168 and $175, 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 Toronto Region of Waterloo 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 Air Tahiti Nui (100%), Qatar Airways (85%) or Alaska Airlines (85%) 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 $350 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $154 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $273.

  • 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 July is currently the most expensive (average of $411). 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 Ontario?

Book flights to Ontario if you plan to visit one of these locations
SeaTac
Tukwila
Tacoma
Lakewood
Renton
Lacey
Ocean Shores
Leavenworth
Federal Way
Olympia
Cle Elum
Centralia
Mukilteo
Aberdeen
Shoreline
Lynnwood
Shelton
Silverdale
Redmond
Monroe

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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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Kingston to Seattle flights

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 mars 25, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$122Average$457FlexibilityNo cancel feeOn-time67%
WestJetCheapest$164Average$412FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$239Average$414FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$240Average$439FlexibilityNo cancel feeOn-time69%
DeltaCheapest$292Average$451FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$393Average$653FlexibilityNo cancel feeOn-time71%
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