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Cheap flights from Ontario to Seattle from C$ 170

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 15/7. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
7 Jul — 14 Jul1
1 adult

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 2 July 2025.

Round-trip from

C$ 267

One-way from

C$ 170

Popular in

July

Cheapest in

February

Average price

C$ 587

Good round-trip deal

C$ 576 or less

Good one-way deal

C$ 267 or less
WestJet
  • WestJet
  • 18/8-25/8
  • 2 total stops
  • 17h 34m total
  • Ontario to Seattle
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WestJet
  • WestJet
  • 15/7
  • 1 total stop
  • 9h 58m total
  • Ontario to Seattle
Search Deals
Highest demand for flights based on searches. 10% potential increase in price (C$ 81 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease (C$ 13 potential savings vs. average RT price).
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Average for round-trip flights in July 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 2 July 2025.

Mon 18/86:00 a.m.YHM - SEA
1 stop9h 58mWestJet
Mon 25/82:05 p.m.SEA - YHM
1 stop7h 36mWestJet
Deal found 30/6C$ 267
Thu 14/88:00 p.m.YXU - SEA
1 stop27h 28mWestJet
Thu 21/87:35 p.m.SEA - YXU
1 stop6h 39mWestJet
Deal found 30/6C$ 333
Thu 14/89:55 a.m.YXU - SEA
2 stops13h 46mMultiple Airlines
Thu 21/87:35 p.m.SEA - YXU
1 stop6h 39mMultiple Airlines
Deal found 30/6C$ 343
Fri 15/86:00 a.m.YKF - SEA
1 stop17h 28mWestJet
Fri 22/81:50 p.m.SEA - YKF
1 stop7h 56mWestJet
Deal found 1/7C$ 349
Fri 25/73:00 p.m.YYZ - SEA
1 stop8h 28mWestJet
Sat 2/87:35 p.m.SEA - YYZ
1 stop7h 37mWestJet
Deal found 2/7C$ 349
Tue 8/74:10 p.m.YTZ - SEA
2 stops9h 06mAir Canada
Tue 15/75:30 a.m.SEA - YTZ
2 stops12h 11mAir Canada
Deal found 1/7C$ 352
Fri 18/712:45 p.m.YYZ - SEA
1 stop15h 11mUnited Airlines
Fri 7/116:20 a.m.SEA - YYZ
1 stop8h 34mUnited Airlines
Deal found 1/7C$ 364
Mon 6/1010:00 a.m.YYZ - SEA
2 stops12h 31mAir Canada
Mon 13/107:15 a.m.SEA - YYZ
1 stop8h 19mAir Canada
Deal found 1/7C$ 365
Thu 4/126:15 a.m.YYZ - SEA
2 stops11h 28mAmerican Airlines
Sat 10/111:54 a.m.SEA - YYZ
1 stop8h 06mAmerican Airlines
Deal found 1/7C$ 383
Tue 29/77:45 p.m.YQG - SEA
1 stop25h 53mWestJet
Thu 31/77:05 a.m.SEA - YQG
1 stop8h 50mWestJet
Deal found 1/7C$ 388
Fri 10/106:00 a.m.YYZ - SEA
1 stop11h 24mDelta
Sun 12/105:45 a.m.SEA - YYZ
1 stop8h 01mDelta
Deal found 1/7C$ 390
Fri 18/79:00 a.m.YYZ - SEA
2 stops14h 28mMultiple Airlines
Mon 21/75:59 p.m.SEA - YYZ
1 stop9h 21mMultiple Airlines
Deal found 1/7C$ 416

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 July 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

Mon 18/8

6:00 a.m.-12:58 p.m.

1 stop9h 58m

Seattle/Tacoma Intl

Mon 25/8

2:05 p.m.-12:41 a.m.

1 stop7h 36m

C$ 267

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 14/8

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

1 stop27h 28m

Seattle/Tacoma Intl

Thu 21/8

7:35 p.m.-5:14 a.m.

1 stop6h 39m

C$ 333

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 14/8

9:55 a.m.-8:41 p.m.

2 stops13h 46m

Seattle/Tacoma Intl

Thu 21/8

7:35 p.m.-5:14 a.m.

1 stop6h 39m

C$ 343

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 15/8

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

1 stop17h 28m

Seattle/Tacoma Intl

Fri 22/8

1:50 p.m.-12:46 a.m.

1 stop7h 56m

C$ 349

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 25/7

3:00 p.m.-8:28 p.m.

1 stop8h 28m

Seattle/Tacoma Intl

Sat 2/8

7:35 p.m.-6:12 a.m.

1 stop7h 37m

C$ 349

TorontoSeattle

YTZ - SEA

YTZSEA

Toronto Island

Mon 6/10

12:25 p.m.-7:31 p.m.

1 stop10h 06m

Seattle/Tacoma Intl

Sun 12/10

7:15 p.m.-11:45 a.m.

2 stops13h 30m

C$ 357

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 18/7

12:45 p.m.-12:56 a.m.

1 stop15h 11m

Seattle/Tacoma Intl

Fri 7/11

6:20 a.m.-5:54 p.m.

1 stop8h 34m

C$ 364

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Mon 6/10

10:00 a.m.-7:31 p.m.

2 stops12h 31m

Seattle/Tacoma Intl

Mon 13/10

7:15 a.m.-6:34 p.m.

1 stop8h 19m

C$ 365

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Thu 4/12

6:15 a.m.-2:43 p.m.

2 stops11h 28m

Seattle/Tacoma Intl

Sat 10/1

11:54 a.m.-11:00 p.m.

1 stop8h 06m

C$ 383

WindsorSeattle

YQG - SEA

YQGSEA

Windsor

Tue 29/7

7:45 p.m.-6:38 p.m.

1 stop25h 53m

Seattle/Tacoma Intl

Thu 31/7

7:05 a.m.-6:55 p.m.

1 stop8h 50m

C$ 388

Flights are sorted by cheapest round-trip flights first.

Deals found on 30/6

Showing 1-10 of 52 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 C$ 262). Flying from Region of Ontario to Seattle in December is currently the most expensive (average of C$ 353). 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 July 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 2 July 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 (2 on average).

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 2 July 2025.
Check out reviews from past customers who have flown with Alaska Airlines,Delta, andUnited Airlines from Ontario to Seattle to help guide your decision. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.1

Food

7.1

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
Check prices

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.1

Food

7.1

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
7,983 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.1

Food

7.1

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
8,861 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.1

Food

7.1

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
Check prices

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.1

Food

7.1

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
WestJet
7.2
Good
2,912 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.1

Food

7.1

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?

    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.

  • 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$ 170. Users have also found prices from C$ 213 and C$ 234 on Air Canada and United 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 Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl or Toronto Region of Waterloo 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 Alaska Airlines (90%), Hawaiian Airlines (90%) or Air Tahiti Nui (85%) 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$ 197. While the most popular route (Toronto Pearson Intl - Seattle/Tacoma Intl) can be booked for C$ 343 on average our data indicates C$ 522 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$ 262). Flying from Region of Ontario to Seattle in December is currently the most expensive (average of C$ 353). 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 Ontario?

Book flights to Ontario if you plan to visit one of these locations
Leavenworth
Tukwila
SeaTac
Tacoma
Marysville
Bothell
Renton
Olympia
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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Edmonton to Spokane flights
Edmonton to Portland flights
Pearson Intl to Spokane flights
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Ottawa to Portland flights
Toronto Island to Portland flights
Regina to Seattle flights
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London to Seattle flights
Pierre Elliott Trudeau Intl to Spokane flights
Vancouver Intl to Bellingham flights
Québec City to Portland flights
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Calgary to Spokane flights
Fort St. John to Spokane flights
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Prince George to Seattle flights
Windsor to Seattle flights
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 629,999 searches. Data last updated 2 July 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 188AverageC$ 421FlexibilityNo cancel feeOn-time60%
Search WestJet flights
United AirlinesCheapestC$ 274AverageC$ 488FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Alaska AirlinesCheapestC$ 328AverageC$ 497FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Air CanadaCheapestC$ 351AverageC$ 496FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
DeltaCheapestC$ 369AverageC$ 516FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Hawaiian AirlinesCheapestC$ 405AverageC$ 451FlexibilityNo cancel feeOn-time85%
Search Hawaiian Airlines flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

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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