HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Seattle

$149+ 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 10/8. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
ago. 4 — ago. 111
lun. 8/4
lun. 8/11
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to Seattle with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 julio 30, 2025.

Round-trip from

$227
(Air Canada)

One-way from

$149
(Alaska Airlines)

Popular in

December

Cheapest in

February

Average price

$402

Good round-trip deal

$349 or less

Good one-way deal

$209 or less
From Ontario to Seattle/Tacoma Intl
Search Deals
One-way flight from Ontario to Seattle/Tacoma Intl
Search Deals
High demand for flights, 4% potential price rise
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($5 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 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

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 julio 30, 2025.

This Air Canada deal was found by Cheapflights users on 7/29. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 9/52:00 pmYYZ - SEA
1 stop7h 36mAir Canada
dom. 9/147:15 pmSEA - YYZ
1 stop8h 45mAir Canada
Deal found 7/29$227
This FlightHub deal was found by Cheapflights users on 7/30. 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.
mié. 9/171:30 pmYYZ - SEA
1 stop9h 59mWestJet
mar. 9/232:05 pmSEA - YYZ
1 stop7h 17mWestJet
Deal found 7/30$228
This Air Canada deal was found by Cheapflights users on 7/29. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 8/194:10 pmYTZ - SEA
2 stops9h 06mAir Canada
mar. 9/95:30 amSEA - YTZ
2 stops12h 11mAir Canada
Deal found 7/29$237
This Alaska Airlines deal was found by Cheapflights users on 7/30. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 10/14:45 pmYYZ - SEA
Nonstop5h 23mAlaska Airlines
dom. 10/57:18 amSEA - YYZ
Nonstop4h 42mAlaska Airlines
Deal found 7/30$253
This FlightHub deal was found by Cheapflights users on 7/29. 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.
vie. 8/226:00 amYKF - SEA
1 stop9h 58mWestJet
jue. 8/281:50 pmSEA - YKF
1 stop7h 56mWestJet
Deal found 7/29$265
This Trip.com deal was found by Cheapflights users on 7/29. 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.
mar. 8/196:00 amYHM - SEA
1 stop9h 58mWestJet
mié. 8/271:50 pmSEA - YHM
1 stop7h 51mWestJet
Deal found 7/29$271
This Mytrip deal was found by Cheapflights users on 7/30. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
dom. 9/216:15 amYKF - SEA
1 stop9h 18mMultiple Airlines
mar. 9/305:30 amSEA - YKF
3 stops21h 00mMultiple Airlines
Deal found 7/30$304
This FlightHub deal was found by Cheapflights users on 7/28. 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.
sáb. 9/66:00 amYOW - SEA
1 stop9h 59mWestJet
mar. 9/167:05 amSEA - YOW
1 stop8h 15mWestJet
Deal found 7/28$330
This Kiwi.com deal was found by Cheapflights users on 7/29. 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.
mié. 8/2012:20 pmYOW - SEA
2 stops11h 08mMultiple Airlines
dom. 9/71:15 pmSEA - YOW
1 stop20h 48mMultiple Airlines
Deal found 7/29$356
This Booking.com deal was found by Cheapflights users on 7/28. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 9/234:45 pmYUL - SEA
1 stop8h 31mAir Canada
mié. 10/17:15 amSEA - YUL
Nonstop5h 13mAir Canada
Deal found 7/28$381
This FlightHub deal was found by Cheapflights users on 7/30. 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.
mié. 9/107:00 amYUL - SEA
1 stop8h 59mWestJet
jue. 9/181:50 pmSEA - YUL
1 stop7h 51mWestJet
Deal found 7/30$383
This American Airlines deal was found by Cheapflights users on 7/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 8/254:05 pmYUL - SEA
1 stop9h 21mAmerican Airlines
lun. 8/2512:46 amSEA - YUL
1 stop12h 56mAmerican Airlines
Deal found 7/29$405

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 julio 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

vie. 9/5

2:00 pm-6:36 pm

1 stop7h 36m

Seattle/Tacoma Intl

dom. 9/14

7:15 pm-7:00 am

1 stop8h 45m

$227

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

mié. 9/17

1:30 pm-8:29 pm

1 stop9h 59m

Seattle/Tacoma Intl

mar. 9/23

2:05 pm-12:22 am

1 stop7h 17m

$228

TorontoSeattle

YTZ - SEA

YTZSEA

Toronto Island

mar. 8/19

3:25 pm-8:45 pm

1 stop8h 20m

Seattle/Tacoma Intl

mar. 9/9

7:15 am-7:49 pm

1 stop9h 34m

$237

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

mié. 10/1

4:45 pm-7:08 pm

Nonstop5h 23m

Seattle/Tacoma Intl

dom. 10/5

7:18 am-3:00 pm

Nonstop4h 42m

$253

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

vie. 8/22

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

jue. 8/28

1:50 pm-12:46 am

1 stop7h 56m

$265

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

mar. 8/19

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

mié. 8/27

1:50 pm-12:41 am

1 stop7h 51m

$271

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

dom. 9/21

6:15 am-6:36 pm

2 stops15h 21m

Seattle/Tacoma Intl

mar. 9/30

5:30 am-5:30 am

3 stops21h 00m

$304

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

sáb. 9/6

6:00 am-12:59 pm

1 stop9h 59m

Seattle/Tacoma Intl

mar. 9/16

7:05 am-6:20 pm

1 stop8h 15m

$330

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

mié. 8/20

12:20 pm-8:28 pm

2 stops11h 08m

Seattle/Tacoma Intl

dom. 9/7

1:15 pm-1:03 pm

1 stop20h 48m

$356

MontrealSeattle

YUL - SEA

YULSEA

Montreal Pierre Elliott Trudeau Intl

mar. 9/23

4:45 pm-10:16 pm

1 stop8h 31m

Seattle/Tacoma Intl

mié. 10/1

7:15 am-3:28 pm

Nonstop5h 13m

$381

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Showing 1-10 of 39 results
1
2
3
4

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 June is currently the most expensive (average of $389). 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 julio 30, 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 julio 30, 2025.

The most flights from CAON to SEA are scheduled on a Tuesday (6 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (3 on average).

How much does it cost to fly round-trip from Region of Ontario to Seattle?

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 julio 30, 2025.
Read through reviews of airlines operating flights from Ontario to Seattle, such as Alaska Airlines, Delta, and United Airlines. 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

Boarding

8.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

YEG - SEA

Alaska airline excellent airline pilot smooth, landing, crew staff very nice friendly behave
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

YEG - SEA

Alaska airline excellent airline pilot smooth, landing, crew staff very nice friendly behave
Delta
8.0
Very good
7,980 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

YEG - SEA

Alaska airline excellent airline pilot smooth, landing, crew staff very nice friendly behave
United Airlines
7.4
Good
8,896 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

YEG - SEA

Alaska airline excellent airline pilot smooth, landing, crew staff very nice friendly behave
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

YEG - SEA

Alaska airline excellent airline pilot smooth, landing, crew staff very nice friendly behave
WestJet
7.2
Good
2,975 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

YEG - SEA

Alaska airline excellent airline pilot smooth, landing, crew staff very nice friendly behave

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?

    $149 is the cheapest one-way deal found within the past few days, from Alaska Airlines. You may also be able to find cheap deals on WestJet and Air Canada, with prices starting from $152 and $153, 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 Air Tahiti Nui (94%), Alaska Airlines (93%) or Hawaiian Airlines (93%) 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 $1,247 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $140 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $213.

  • 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 June is currently the most expensive (average of $389). 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
Ocean Shores
Lakewood
Lynnwood
Lacey
Leavenworth
Renton
Olympia
Puyallup
Kent
Cle Elum
Chehalis
Kirkland
Issaquah
Aberdeen
Shoreline
Federal Way
Shelton

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to Seattle

See prices for flight routes from nearby airports that may be better suited for you.
Pearson Intl to Seattle flights
Vancouver Intl to Seattle flights
Pierre Elliott Trudeau Intl to Seattle flights
Calgary to Seattle flights
Vancouver Intl to Portland flights
Calgary to Portland flights
Edmonton to Seattle flights
Pearson Intl to Portland flights
Region of Waterloo Intl to Seattle flights
Victoria to Seattle flights
Vancouver Intl to Spokane flights
Pierre Elliott Trudeau Intl to Portland flights
Ottawa to Seattle flights
Kelowna to Seattle flights
Hamilton to Portland flights
Québec City to Seattle flights
Winnipeg to Seattle flights
Victoria to Portland flights
Pearson Intl to Spokane flights
Kelowna to Portland flights
Toronto Island to Portland flights
Edmonton to Portland flights
Saskatoon to Seattle flights
Halifax to Seattle flights
Ottawa to Portland flights
Calgary to Spokane flights
London to Portland flights
Regina to Seattle flights
Prince George to Seattle flights
Winnipeg to Portland flights
Pierre Elliott Trudeau Intl to Spokane flights
Saskatoon to Portland flights
London to Seattle flights
Windsor to Portland flights
Kamloops to Portland flights
St John to Portland flights
Kingston to Seattle flights
Pierre Elliott Trudeau Intl to Pasco flights
Fort St. John to Portland 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 julio 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$213Average$389FlexibilityNo cancel feeOn-time60%
United AirlinesCheapest$240Average$446FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$243Average$402FlexibilityNo cancel feeOn-time75%
Air CanadaCheapest$250Average$465FlexibilityNo cancel feeOn-time67%
American AirlinesCheapest$277Average$277FlexibilityNo cancel feeOn-time71%
DeltaCheapest$289Average$353FlexibilityNo cancel feeOn-timeN/A

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.