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$131+ 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 9/23. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 June 12, 2025.

Round-trip from

$215
(Trip.com)

One-way from

$131
(FlightHub)

Popular in

July

Cheapest in

February

Average price

$408

Good round-trip deal

$413 or less

Good one-way deal

$258 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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Highest demand for flights based on searches. 10% potential increase in price ($40 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($7 potential savings vs. average RT price).
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Average for round-trip flights in June 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 June 12, 2025.

This Trip.com deal was found by Cheapflights users on 6/10. 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.
Wed 8/206:00 amYHM - SEA
1 stop9h 58mWestJet
Thu 10/231:50 pmSEA - YHM
1 stop7h 50mWestJet
Deal found 6/10$215
This Trip.com deal was found by Cheapflights users on 6/10. 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.
Fri 10/36:00 amYXU - SEA
1 stop9h 59mWestJet
Sat 10/117:05 amSEA - YXU
1 stop9h 02mWestJet
Deal found 6/10$241
This WestJet deal was found by Cheapflights users on 6/10. 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 WestJet is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/287:45 pmYKF - SEA
2 stops19h 46mWestJet
Fri 9/51:50 pmSEA - YKF
1 stop7h 55mWestJet
Deal found 6/10$256
This FlightHub deal was found by Cheapflights users on 6/9. 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 7/21:30 pmYYZ - SEA
1 stop9h 58mWestJet
Sun 7/62:05 pmSEA - YYZ
1 stop7h 19mWestJet
Deal found 6/9$257
This Air Canada deal was found by Cheapflights users on 6/11. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/79:00 pmYYZ - SEA
1 stop15h 16mAir Canada
Sun 11/167:30 amSEA - YYZ
Nonstop4h 39mAir Canada
Deal found 6/11$261
This Air Canada deal was found by Cheapflights users on 6/10. 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 8/267:20 pmYTZ - SEA
2 stops17h 01mAir Canada
Fri 9/57:15 amSEA - YTZ
1 stop9h 34mAir Canada
Deal found 6/10$266
This Orbitz deal was found by Cheapflights users on 6/11. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/164:45 pmYYZ - SEA
Nonstop5h 24mMultiple Airlines
Sat 8/307:05 amSEA - YYZ
1 stop8h 49mMultiple Airlines
Deal found 6/11$267
This United Airlines deal was found by Cheapflights users on 6/9. 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 7/1210:05 amYYZ - SEA
1 stop17h 51mUnited Airlines
Tue 7/1512:20 amSEA - YYZ
1 stop12h 26mUnited Airlines
Deal found 6/9$268
This Delta deal was found by Cheapflights users on 6/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/235:43 pmYYZ - SEA
1 stop7h 32mDelta
Sat 8/305:30 amSEA - YYZ
1 stop8h 08mDelta
Deal found 6/11$270
This Alaska Airlines deal was found by Cheapflights users on 6/10. 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.
Sun 8/314:45 pmYYZ - SEA
Nonstop5h 22mAlaska Airlines
Thu 9/187:16 amSEA - YYZ
Nonstop4h 44mAlaska Airlines
Deal found 6/10$283
This Air Canada deal was found by Cheapflights users on 6/10. 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.
Fri 10/36:15 amYXU - SEA
1 stop7h 44mAir Canada
Sat 10/117:15 amSEA - YXU
2 stops11h 12mAir Canada
Deal found 6/10$286
This oojo deal was found by Cheapflights users on 6/10. 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 9/43:45 pmYOW - SEA
1 stop7h 44mWestJet
Sun 9/142:05 pmSEA - YOW
1 stop7h 35mWestJet
Deal found 6/10$296

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 June 12, 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

Wed 8/20

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

Thu 10/23

1:50 pm-12:40 am

1 stop7h 50m

$215

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 10/3

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

Sat 10/11

7:05 am-7:07 pm

1 stop9h 02m

$241

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 8/28

7:45 pm-12:31 pm

2 stops19h 46m

Seattle/Tacoma Intl

Fri 9/5

1:50 pm-12:45 am

1 stop7h 55m

$256

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 7/2

1:30 pm-8:28 pm

1 stop9h 58m

Seattle/Tacoma Intl

Sun 7/6

2:05 pm-12:24 am

1 stop7h 19m

$257

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 11/7

9:00 pm-9:16 am

1 stop15h 16m

Seattle/Tacoma Intl

Sun 11/16

7:30 am-3:09 pm

Nonstop4h 39m

$261

TorontoSeattle

YTZ - SEA

YTZSEA

Toronto Island

Tue 8/26

7:20 pm-9:21 am

2 stops17h 01m

Seattle/Tacoma Intl

Fri 9/5

7:15 am-7:49 pm

1 stop9h 34m

$266

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 8/16

4:45 pm-7:09 pm

Nonstop5h 24m

Seattle/Tacoma Intl

Sat 8/30

7:05 am-6:54 pm

1 stop8h 49m

$267

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 7/12

10:05 am-12:56 am

1 stop17h 51m

Seattle/Tacoma Intl

Tue 7/15

12:20 am-3:46 pm

1 stop12h 26m

$268

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 8/23

5:43 pm-10:15 pm

1 stop7h 32m

Seattle/Tacoma Intl

Sat 8/30

5:30 am-4:38 pm

1 stop8h 08m

$270

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sun 8/31

4:45 pm-7:07 pm

Nonstop5h 22m

Seattle/Tacoma Intl

Thu 9/18

7:16 am-3:00 pm

Nonstop4h 44m

$283

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 54 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 $391). 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 June 12, 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 June 12, 2025.

The most flights from CAON to SEA are scheduled on a Monday (5 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (3 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 June 12, 2025.
Read reviews from past customers who have flown Alaska Airlines, Delta and Hawaiian 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
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

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
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

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
7,946 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

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
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

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
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

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
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

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?

    $131 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 Delta, with prices starting from $176 and $178, 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 (85%), Hawaiian Airlines (85%) or Air Tahiti Nui (76%) 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 $380 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $159 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 $238). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of $391). 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
Ocean Shores
Lacey
Leavenworth
Federal Way
Lynnwood
Olympia
Shoreline
Kent
Cle Elum
Centralia
Kirkland
Aberdeen
Renton
Shelton
Silverdale
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.
Vancouver Intl to Seattle flights
Pearson Intl to Seattle flights
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Pierre Elliott Trudeau Intl to Seattle flights
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Victoria to Portland flights
Edmonton to Portland flights
Saskatoon to Portland flights
Pearson Intl to Spokane flights
Kelowna to Portland flights
Pierre Elliott Trudeau Intl to Spokane flights
Calgary to Spokane flights
Halifax to Seattle flights
Winnipeg to Seattle flights
Windsor to Portland flights
Kamloops to Portland flights
Regina to Seattle flights
London to Seattle flights
Prince George to Seattle flights
St John to Portland flights
Fort St. John to Portland flights
Kingston to Seattle flights
London to Portland flights
Pierre Elliott Trudeau Intl to Pasco flights

Top 5 airlines flying from Ontario to Seattle

Discover the top 5 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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$141Average$343FlexibilityNo cancel feeOn-time60%
United AirlinesCheapest$240Average$446FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$246Average$415FlexibilityNo cancel feeOn-time75%
Air CanadaCheapest$250Average$448FlexibilityNo cancel feeOn-time67%
DeltaCheapest$292Average$421FlexibilityNo cancel feeOn-timeN/A

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