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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 28/4. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
11 Jan — 18 Jan1
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 12 December 2025.

Thu 25/1210:00 a.m.YYZ - SEA
1 stop13h 57mUnited Airlines
Wed 7/110:58 a.m.SEA - YYZ
1 stop7h 23mUnited Airlines
Deal found 10/12C$ 485
Wed 31/127:40 p.m.YYZ - SEA
2 stops17h 15mUnited Airlines
Sun 15/211:35 p.m.SEA - YYZ
1 stop9h 13mUnited Airlines
Deal found 10/12C$ 512
Fri 26/126:30 a.m.YYZ - SEA
1 stop17h 37mUnited Airlines
Wed 7/12:10 p.m.SEA - YYZ
1 stop16h 48mUnited Airlines
Deal found 11/12C$ 548
Thu 25/1210:00 a.m.YYZ - SEA
1 stop13h 57mUnited Airlines
Thu 1/111:59 p.m.SEA - YYZ
1 stop6h 59mUnited Airlines
Deal found 9/12C$ 549
Wed 24/128:30 a.m.YYZ - SEA
1 stop12h 36mUnited Airlines
Tue 6/19:00 a.m.SEA - YYZ
2 stops22h 40mUnited Airlines
Deal found 9/12C$ 570
Wed 24/126:30 a.m.YYZ - SEA
1 stop15h 15mUnited Airlines
Thu 1/111:59 p.m.SEA - YYZ
1 stop6h 59mUnited Airlines
Deal found 9/12C$ 610
Wed 24/125:25 p.m.YUL - SEA
1 stop19h 30mUnited Airlines
Mon 19/17:00 a.m.SEA - YUL
1 stop8h 40mUnited Airlines
Deal found 10/12C$ 623
Mon 29/1210:45 a.m.YYZ - SEA
1 stop13h 22mUnited Airlines
Wed 31/125:02 a.m.SEA - YYZ
1 stop14h 39mUnited Airlines
Deal found 10/12C$ 629
Thu 25/1210:00 a.m.YYZ - SEA
1 stop13h 57mUnited Airlines
Fri 26/1211:15 p.m.SEA - YYZ
1 stop16h 42mUnited Airlines
Deal found 9/12C$ 639
Thu 25/121:15 p.m.YUL - SEA
2 stops12h 01mAir Canada
Tue 30/125:50 a.m.SEA - YUL
1 stop8h 10mAir Canada
Deal found 9/12C$ 709
Thu 25/123:00 p.m.YTZ - SEA
1 stop11h 05mMultiple Airlines
Sat 27/125:49 p.m.SEA - YTZ
2 stops13h 46mMultiple Airlines
Deal found 11/12C$ 786
Mon 29/125:25 p.m.YUL - SEA
1 stop19h 31mUnited Airlines
Wed 4/28:40 a.m.SEA - YUL
2 stops23h 50mUnited Airlines
Deal found 10/12C$ 790

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 12 December 2025.

Round-trip from

C$ 274

One-way from

C$ 210

Popular in

June

Cheapest in

February

Average price

C$ 556

Good round-trip deal

C$ 357 or less

Good one-way deal

C$ 292 or less
Alaska Airlines
  • Alaska Airlines
  • 14/1-28/1
  • Nonstop
  • 10h 12m total
  • Ontario to Seattle
Search Deals
Air Canada
  • Air Canada
  • 25/4
  • Nonstop
  • 5h 21m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 10% potential increase in price (C$ 78 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease (C$ 11 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 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

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 12 December 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

Sat 14/3

4:45 p.m.-7:18 p.m.

Nonstop5h 33m

Seattle/Tacoma Intl

Tue 17/3

7:55 a.m.-3:35 p.m.

Nonstop4h 40m

C$ 290

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 21/1

4:45 p.m.-7:17 p.m.

Nonstop5h 32m

Seattle/Tacoma Intl

Sun 1/2

7:55 a.m.-3:35 p.m.

Nonstop4h 40m

C$ 301

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 28/1

4:45 p.m.-7:17 p.m.

Nonstop5h 32m

Seattle/Tacoma Intl

Thu 5/2

7:55 a.m.-3:35 p.m.

Nonstop4h 40m

C$ 302

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sun 25/1

7:50 p.m.-10:16 p.m.

Nonstop5h 26m

Seattle/Tacoma Intl

Sun 1/2

8:10 a.m.-3:53 p.m.

Nonstop4h 43m

C$ 303

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 30/1

4:45 p.m.-7:17 p.m.

Nonstop5h 32m

Seattle/Tacoma Intl

Mon 2/2

7:55 a.m.-3:35 p.m.

Nonstop4h 40m

C$ 313

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 30/1

4:45 p.m.-7:17 p.m.

Nonstop5h 32m

Seattle/Tacoma Intl

Sun 1/2

7:55 a.m.-3:35 p.m.

Nonstop4h 40m

C$ 313

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 22/5

6:00 a.m.-8:28 p.m.

1 stop17h 28m

Seattle/Tacoma Intl

Mon 25/5

7:05 a.m.-12:45 a.m.

1 stop14h 40m

C$ 317

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 30/4

6:00 a.m.-8:28 p.m.

1 stop17h 28m

Seattle/Tacoma Intl

Thu 7/5

7:05 a.m.-12:45 a.m.

1 stop14h 40m

C$ 319

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

Wed 8/4

5:40 a.m.-2:19 p.m.

2 stops11h 39m

Seattle/Tacoma Intl

Tue 14/4

3:10 p.m.-12:39 a.m.

2 stops30h 29m

C$ 331

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 24/1

6:50 a.m.-6:28 p.m.

2 stops14h 38m

Seattle/Tacoma Intl

Sat 31/1

11:45 p.m.-11:48 a.m.

1 stop9h 03m

C$ 334

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/12

Showing 1-10 of 60 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, December is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 181). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 343). 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 12 December 2025.

Unlike in the afternoon, when flights are generally more expensive, you can save up to 19% on flights from Region of Ontario to Seattle by exploring options for tickets in the evening.

What is the cheapest day to fly from Region of Ontario to Seattle?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Seattle. Price data was last updated on 16 December 2024.

Travelers seeking maximum savings on their Region of Ontario to Seattle flight should consider departing on Thursday evenings when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

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 12 December 2025.

The most flights from CAON to SEA are scheduled on a Thursday (7 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (5 on average).

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 5h 26m. The distance from Region of Ontario to Seattle is about 3306 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$ 183. Users have also found prices from C$ 193 and C$ 207 on Alaska Airlines and Air Canada, 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 Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl or Ottawa - 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 Hawaiian Airlines (84%), Air Tahiti Nui (84%) or Qatar Airways (78%) 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$ 155. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 281 on average, our data indicates C$ 440 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, December is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 181). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 343). 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
Leavenworth
SeaTac
Tukwila
Mukilteo
Tacoma
Bothell
Cashmere
Olympia
Renton
Marysville
Lynnwood

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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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Saskatoon to Portland flights
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Windsor 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 629,999 searches. Data last updated 12 December 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 182AverageC$ 404FlexibilityNo cancel feeOn-time60%
Search WestJet flights
United AirlinesCheapestC$ 277AverageC$ 484FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Alaska AirlinesCheapestC$ 288AverageC$ 477FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Air CanadaCheapestC$ 337AverageC$ 538FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
DeltaCheapestC$ 342AverageC$ 492FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Hawaiian AirlinesCheapestC$ 410AverageC$ 463FlexibilityNo 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?

900+ travel sites are searched through when a user searches for a flight using Cheapflights. From the search interface, users can use filters to choose airlines, airports, flight times, cabin classes and more to their preference. Book your flight to Seattle from Ontario today with Cheapflights!

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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