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Cheap flights from Ontario to Seattle from C$ 210

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 18/6. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
1 Jun — 8 Jun1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ontario to Seattle

Enter your travel dates to find the best prices.

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 2 May 2026.

Fri 4/91:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Mon 7/910:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Deal found 26/4C$ 307
Sat 5/92:50 p.m.
YYZ
-
SEA
1 stop9h 10m
WestJet
Mon 14/910:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Deal found 1/5C$ 310
Tue 19/512:00 p.m.
YYZ
-
SEA
1 stop9h 45m
WestJet
Tue 26/510:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Deal found 30/4C$ 312
Thu 28/51:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Sat 6/610:30 a.m.
SEA
-
YYZ
1 stop9h 15m
WestJet
Deal found 29/4C$ 316
Wed 15/73:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Sun 2/87:00 a.m.
SEA
-
YYZ
2 stops11h 10m
WestJet
Deal found 28/4C$ 318
Tue 11/83:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Tue 18/87:35 p.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Deal found 28/4C$ 319
Thu 13/812:00 p.m.
YYZ
-
SEA
2 stops9h 45m
WestJet
Thu 20/810:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Deal found 28/4C$ 320
Thu 4/612:00 p.m.
YYZ
-
SEA
2 stops9h 45m
WestJet
Tue 9/610:30 a.m.
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 30/4C$ 322
Sat 11/76:10 a.m.
YYZ
-
SEA
2 stops15h 35m
WestJet
Sun 19/710:30 a.m.
SEA
-
YYZ
2 stops10h 29m
WestJet
Deal found 30/4C$ 325
Wed 24/66:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Wed 15/77:00 a.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Deal found 29/4C$ 339
Wed 5/86:45 a.m.
YUL
-
SEA
2 stops15h 00m
WestJet
Mon 10/87:35 p.m.
SEA
-
YUL
1 stop8h 30m
WestJet
Deal found 30/4C$ 345
Fri 19/66:10 p.m.
YHM
-
SEA
1 stop27h 35m
WestJet
Mon 22/67:00 a.m.
SEA
-
YHM
1 stop7h 15m
WestJet
Deal found 26/4C$ 350

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 2 May 2026.

Round-trip from

C$ 307

One-way from

C$ 210

Popular in

June

Cheapest in

February

Average price

C$ 424

Good round-trip deal

C$ 529 or less

Good one-way deal

C$ 320 or less
WestJet
  • WestJet
  • 4/9-7/9
  • 2 total stops
  • 16h 00m total
  • Ontario to Seattle
Search Deals
WestJet
  • WestJet
  • 18/6
  • 1 total stop
  • 16h 00m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 7% potential increase in price (C$ 47 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 14 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 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 629,999 searches. Data last updated 2 May 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

LondonSeattle

YXU - SEA

YXUSEA

London

Wed 24/6

6:10 a.m.-6:45 p.m.

1 stop15h 35m

Seattle/Tacoma Intl

Wed 15/7

7:00 a.m.-4:45 p.m.

1 stop6h 45m

C$ 339

MontrealSeattle

YUL - SEA

YULSEA

Montreal Pierre Elliott Trudeau Intl

Wed 5/8

6:45 a.m.-6:45 p.m.

2 stops15h 00m

Seattle/Tacoma Intl

Mon 10/8

7:35 p.m.-7:05 a.m.

1 stop8h 30m

C$ 345

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 28/5

5:55 p.m.-6:45 p.m.

1 stop27h 50m

Seattle/Tacoma Intl

Tue 2/6

7:35 p.m.-5:20 a.m.

1 stop6h 45m

C$ 353

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 11/5

8:40 p.m.-9:40 a.m.

1 stop16h 00m

Seattle/Tacoma Intl

Sat 16/5

7:35 p.m.-7:50 p.m.

1 stop21h 15m

C$ 368

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 11/6

8:40 p.m.-9:40 a.m.

1 stop16h 00m

Seattle/Tacoma Intl

Mon 22/6

7:00 a.m.-7:50 p.m.

1 stop9h 50m

C$ 372

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Wed 17/6

8:40 p.m.-9:40 a.m.

1 stop16h 00m

Seattle/Tacoma Intl

Tue 23/6

7:00 a.m.-7:50 p.m.

1 stop9h 50m

C$ 377

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Thu 28/5

2:20 p.m.-10:48 p.m.

1 stop11h 28m

Seattle/Tacoma Intl

Sat 6/6

9:35 a.m.-10:59 p.m.

1 stop10h 24m

C$ 391

MontrealSeattle

YUL - SEA

YULSEA

Montreal Pierre Elliott Trudeau Intl

Sun 23/8

6:45 a.m.-6:45 p.m.

2 stops15h 00m

Seattle/Tacoma Intl

Mon 31/8

10:30 a.m.-12:25 a.m.

2 stops10h 55m

C$ 396

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 11/6

5:55 p.m.-6:45 p.m.

1 stop27h 50m

Seattle/Tacoma Intl

Thu 18/6

7:35 p.m.-5:20 a.m.

1 stop6h 45m

C$ 399

MontrealSeattle

YUL - SEA

YULSEA

Montreal Pierre Elliott Trudeau Intl

Wed 29/7

6:45 a.m.-6:45 p.m.

2 stops15h 00m

Seattle/Tacoma Intl

Sun 2/8

7:00 a.m.-4:45 p.m.

2 stops30h 45m

C$ 407

Flights are sorted by cheapest round-trip flights first.

Deals found on 29/4

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

How far ahead should I book a flight from Region of Ontario to Seattle?

Booking 85 days in advance of your planned departure date is, on average, the best time to get cheap flights from Region of Ontario to Seattle. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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 C$ 86). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of C$ 1,084). 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 2 May 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 2 May 2026.

The most flights from CAON to SEA are scheduled on a Wednesday (3 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (1 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?

    Located just 18.4 km from the city centre, Seattle/Tacoma Intl (SEA) is the airport most travelers will use when flying to Seattle from Ontario.

  • How long is the flight from Region of Ontario to Seattle?

    Departing from Region of Ontario to Seattle will take you 7h 59m. The distance from Region of Ontario to Seattle is about 3117 km. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    For one-way options, check prices for WestJet. According to our data, you can fly for as low as C$ 119. Users have also found prices from C$ 161 and C$ 166 on United Airlines and Alaska Airlines, respectively.

  • What are the most popular routes from Region of Ontario to Seattle?

    The most popular route from Region of Ontario to Seattle is Toronto Pearson Intl - Seattle/Tacoma Intl. You may also consider Toronto Island - Seattle/Tacoma Intl or Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl.

  • 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 (93%), Alaska Airlines (70%) or Hawaiian Airlines (70%) 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?

    Looking at all options, your cheapest flight can be booked for C$ 263. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 297 on average, our data indicates C$ 551 when flying from Region of Ontario to Seattle.

  • 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 C$ 86). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of C$ 1,084). 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

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Leavenworth
Mukilteo
Kent
Tacoma
Bothell
Cashmere
Olympia
Renton
Marysville
Lynnwood
Kirkland
Tukwila

Browse thousands of different options on Cheapflights for your next trip

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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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Region of Waterloo Intl to Portland flights
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Pearson Intl to Pasco flights
Regina to Portland flights
Fort St. John to Portland flights
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Prince George to Seattle flights
Regina to Seattle flights
Vancouver Intl to Pullman flights
Pierre Elliott Trudeau Intl to Spokane flights
Nanaimo to Portland flights
Fort St. John to Spokane flights
Windsor to Seattle flights
Kelowna to Bellingham flights
Pearson Intl to Wenatchee 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 629,999 searches. Data last updated 2 May 2026.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 247AverageC$ 587FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
WestJetCheapestC$ 265AverageC$ 416FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 267AverageC$ 448FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
DeltaCheapestC$ 274AverageC$ 482FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Air CanadaCheapestC$ 292AverageC$ 529FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
Hawaiian AirlinesCheapestC$ 368AverageC$ 640FlexibilityNo cancel feeOn-time85%
Search Hawaiian Airlines flights

Fly with Cheapflights

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How does Cheapflights help users find flights from Ontario to Seattle?

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Why should you use Cheapflights to find cheap flight tickets from Ontario to Seattle?

Millions of users choose and trust Cheapflights to book the best flight deals from Ontario to Seattle for free. We help you search and compare prices from hundreds of airlines for the right flight just for you.

Can Cheapflights find flights from Ontario to Seattle with no change fees?

Need flexible booking options for your flight to Seattle from Ontario? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

Can Cheapflights notify me if prices for flights from Ontario to Seattle become cheaper?

Of course! You can now track prices for flights from Ontario to Seattle and get an alert from Cheapflights when they change. Have a valid email address ready and click the bell icon next to the flight deals above to set up your price alerts.

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