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Cheap flights from Ontario to Seattle from C$ 180

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 29/4. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
31 Dec — 7 Jan1
1 adult
1 adult, Economy, 0 bags

Find 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 1 December 2025.

Sun 14/126:30 a.m.YYZ - SEA
1 stop10h 50mWestJet
Wed 24/123:10 p.m.SEA - YYZ
1 stop18h 18mWestJet
Deal found 30/11C$ 346
Sun 14/124:45 p.m.YYZ - SEA
Nonstop5h 33mMultiple Airlines
Wed 24/123:10 p.m.SEA - YYZ
1 stop18h 18mMultiple Airlines
Deal found 30/11C$ 349
Fri 12/124:45 p.m.YYZ - SEA
Nonstop5h 33mAlaska Airlines
Sat 13/1212:18 a.m.SEA - YYZ
1 stop9h 12mAlaska Airlines
Deal found 28/11C$ 360
Fri 12/126:24 p.m.YYZ - SEA
1 stop8h 01mAmerican Airlines
Sat 13/1212:38 a.m.SEA - YYZ
1 stop8h 52mAmerican Airlines
Deal found 28/11C$ 372
Mon 15/125:55 p.m.YYZ - SEA
1 stop9h 55mUnited Airlines
Tue 30/1211:59 p.m.SEA - YYZ
1 stop13h 03mUnited Airlines
Deal found 30/11C$ 377
Sun 14/125:55 p.m.YYZ - SEA
1 stop9h 55mUnited Airlines
Fri 26/1211:39 p.m.SEA - YYZ
1 stop16h 18mUnited Airlines
Deal found 30/11C$ 387
Sun 14/124:45 p.m.YYZ - SEA
Nonstop5h 33mAlaska Airlines
Tue 30/128:00 a.m.SEA - YYZ
Nonstop4h 35mAlaska Airlines
Deal found 30/11C$ 391
Sun 14/124:45 p.m.YYZ - SEA
Nonstop5h 33mAlaska Airlines
Mon 29/128:00 a.m.SEA - YYZ
Nonstop4h 35mAlaska Airlines
Deal found 30/11C$ 398
Sat 13/127:50 p.m.YYZ - SEA
Nonstop5h 26mAir Canada
Fri 13/38:10 a.m.SEA - YYZ
Nonstop4h 43mAir Canada
Deal found 30/11C$ 408
Tue 16/124:45 p.m.YYZ - SEA
Nonstop5h 33mAlaska Airlines
Wed 31/128:00 a.m.SEA - YYZ
Nonstop4h 35mAlaska Airlines
Deal found 30/11C$ 409
Sun 14/123:50 p.m.YUL - SEA
1 stop21h 08mAmerican Airlines
Mon 15/1210:07 p.m.SEA - YUL
1 stop12h 42mAmerican Airlines
Deal found 30/11C$ 419
Sun 14/1211:10 a.m.YUL - SEA
1 stop14h 06mAir Canada
Sat 10/18:10 a.m.SEA - YUL
1 stop8h 12mAir Canada
Deal found 28/11C$ 427

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 1 December 2025.

Round-trip from

C$ 274

One-way from

C$ 180

Popular in

December

Cheapest in

February

Average price

C$ 636

Good round-trip deal

C$ 370 or less

Good one-way deal

C$ 310 or less
WestJet
  • WestJet
  • 15/5-23/5
  • 2 total stops
  • 16h 03m total
  • Ontario to Seattle
Search Deals
WestJet
  • WestJet
  • 29/4
  • 1 total stop
  • 9h 23m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 1% potential increase in price (C$ 12 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 19 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.
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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 1 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

OttawaSeattle

YOW - SEA

YOWSEA

Ottawa

Fri 15/5

3:45 p.m.-8:28 p.m.

1 stop7h 43m

Seattle/Tacoma Intl

Sat 23/5

7:05 a.m.-6:25 p.m.

1 stop8h 20m

C$ 274

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Thu 30/4

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

1 stop17h 28m

Seattle/Tacoma Intl

Sat 9/5

2:05 p.m.-12:40 a.m.

1 stop7h 35m

C$ 278

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Tue 3/3

5:50 a.m.-2:19 p.m.

1 stop11h 29m

Seattle/Tacoma Intl

Tue 17/3

3:10 p.m.-5:16 p.m.

1 stop23h 06m

C$ 314

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Tue 12/5

6:00 a.m.-1:08 p.m.

1 stop10h 08m

Seattle/Tacoma Intl

Wed 20/5

7:05 a.m.-12:40 a.m.

1 stop14h 35m

C$ 325

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sun 18/1

3:30 p.m.-10:43 p.m.

1 stop10h 13m

Seattle/Tacoma Intl

Wed 28/1

5:00 a.m.-3:02 p.m.

1 stop7h 02m

C$ 327

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Fri 8/5

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

1 stop17h 28m

Seattle/Tacoma Intl

Sat 16/5

2:05 p.m.-12:40 a.m.

1 stop7h 35m

C$ 330

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sat 21/2

6:30 a.m.-9:01 p.m.

1 stop17h 31m

Seattle/Tacoma Intl

Thu 26/2

7:00 a.m.-9:21 p.m.

1 stop11h 21m

C$ 331

LondonSeattle

YXU - SEA

YXUSEA

London

Tue 20/1

5:40 p.m.-10:16 p.m.

1 stop7h 36m

Seattle/Tacoma Intl

Wed 21/1

8:00 p.m.-8:46 a.m.

2 stops9h 46m

C$ 337

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 6/1

9:00 p.m.-11:32 a.m.

1 stop17h 32m

Seattle/Tacoma Intl

Thu 12/2

7:00 a.m.-9:21 p.m.

1 stop11h 21m

C$ 342

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Thu 5/3

6:10 p.m.-2:19 p.m.

1 stop23h 09m

Seattle/Tacoma Intl

Thu 12/3

3:10 p.m.-1:21 p.m.

1 stop19h 11m

C$ 345

Flights are sorted by cheapest round-trip flights first.

Deals found on 29/11

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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, May is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 129). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 348). 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 1 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 1 December 2025.

The most flights from CAON to SEA are scheduled on a Monday (7 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (2 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 36m. The distance from Region of Ontario to Seattle is about 3219 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$ 193. Users have also found prices from C$ 212 and C$ 219 on United 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 Hamilton - Seattle/Tacoma Intl or Toronto Island - 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 (88%), Hawaiian Airlines (81%) or Alaska 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$ 230. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 244 on average, our data indicates C$ 471 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, May is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of C$ 129). Flying from Region of Ontario to Seattle in June is currently the most expensive (average of C$ 348). 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

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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St John to Portland flights
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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 1 December 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 185AverageC$ 411FlexibilityNo cancel feeOn-time60%
Search WestJet flights
United AirlinesCheapestC$ 281AverageC$ 488FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Alaska AirlinesCheapestC$ 299AverageC$ 490FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Air CanadaCheapestC$ 341AverageC$ 558FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
DeltaCheapestC$ 366AverageC$ 500FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Hawaiian AirlinesCheapestC$ 415AverageC$ 469FlexibilityNo 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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