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Cheap flights from Seattle to Ontario from C$ 161

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 26/8. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
3 Aug — 10 Aug1
1 adult

Cheap flight deals from Seattle to Ontario

Keep the following information in mind while searching for Seattle to Ontario flight deals. Data was last updated 29 July 2025.

Round-trip from

C$ 333

One-way from

C$ 161

Popular in

June

Cheapest in

January

Average price

C$ 672

Good round-trip deal

C$ 910 or less

Good one-way deal

C$ 235 or less
WestJet
  • WestJet
  • 12/9-19/9
  • 3 total stops
  • 19h 45m total
  • Seattle to Ontario
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WestJet
  • WestJet
  • 26/8
  • 1 total stop
  • 7h 37m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 13% potential increase in price (C$ 120 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease (C$ 16 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 Seattle/Tacoma Intl to Ontario.
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Price to beat on a one-way flight from Seattle/Tacoma Intl to Ontario.
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Find flight deals from Seattle to Ontario

Cheapest flights from Seattle to Ontario
Explore the most affordable flight options available from Seattle to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 29 July 2025.

Fri 12/91:15 p.m.SEA - YYZ
1 stop8h 16mWestJet
Fri 19/912:00 p.m.YYZ - SEA
2 stops11h 29mWestJet
Deal found 29/7C$ 333
Thu 11/95:30 a.m.SEA - YTZ
2 stops10h 15mAir Canada
Thu 18/94:10 p.m.YTZ - SEA
2 stops9h 06mAir Canada
Deal found 28/7C$ 342
Wed 12/118:15 a.m.SEA - YYZ
Nonstop4h 43mAir Canada
Wed 26/117:30 p.m.YYZ - SEA
Nonstop5h 26mAir Canada
Deal found 29/7C$ 351
Tue 19/82:05 p.m.SEA - YKF
1 stop7h 41mWestJet
Fri 22/86:00 a.m.YKF - SEA
1 stop9h 58mWestJet
Deal found 26/7C$ 380
Fri 12/97:16 a.m.SEA - YYZ
Nonstop4h 44mMultiple Airlines
Fri 19/93:00 p.m.YYZ - SEA
1 stop8h 29mMultiple Airlines
Deal found 29/7C$ 402
Wed 10/98:40 a.m.SEA - YXU
1 stop7h 27mWestJet
Wed 17/96:00 a.m.YXU - SEA
1 stop9h 59mWestJet
Deal found 27/7C$ 405
Tue 9/97:16 a.m.SEA - YYZ
Nonstop4h 44mAlaska Airlines
Sat 20/94:45 p.m.YYZ - SEA
Nonstop5h 23mAlaska Airlines
Deal found 28/7C$ 405
Tue 19/82:05 p.m.SEA - YHM
1 stop7h 36mWestJet
Fri 22/86:00 a.m.YHM - SEA
1 stop9h 58mWestJet
Deal found 26/7C$ 406
Wed 10/97:15 p.m.SEA - YKF
3 stops31h 15mMultiple Airlines
Wed 17/96:30 a.m.YKF - SEA
2 stops18h 46mMultiple Airlines
Deal found 27/7C$ 420
Thu 18/97:05 a.m.SEA - YOW
1 stop8h 15mWestJet
Sun 21/93:45 p.m.YOW - SEA
1 stop7h 44mWestJet
Deal found 29/7C$ 455
Wed 10/97:15 p.m.SEA - YXU
2 stops11h 04mAir Canada
Wed 17/96:10 a.m.YXU - SEA
1 stop7h 49mAir Canada
Deal found 27/7C$ 469
Thu 11/95:30 a.m.SEA - YTZ
2 stops12h 11mMultiple Airlines
Thu 18/95:30 p.m.YTZ - SEA
3 stops18h 52mMultiple Airlines
Deal found 28/7C$ 471

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Ontario 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 29 July 2025.
Use the filters below to find and compare flights from Seattle to Ontario that are best for you.

Fly from

Seattle

Fly to

Ontario

Route

Depart

Return

Price

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Fri 12/9

1:15 p.m.-12:31 a.m.

1 stop8h 16m

Toronto Pearson Intl

Fri 19/9

12:00 p.m.-8:29 p.m.

2 stops11h 29m

C$ 333

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Thu 11/9

5:30 a.m.-6:45 p.m.

2 stops10h 15m

Toronto Island

Thu 18/9

4:10 p.m.-10:16 p.m.

2 stops9h 06m

C$ 342

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Wed 12/11

8:15 a.m.-3:58 p.m.

Nonstop4h 43m

Toronto Pearson Intl

Wed 26/11

7:30 p.m.-9:56 p.m.

Nonstop5h 26m

C$ 351

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Wed 10/9

7:16 a.m.-3:00 p.m.

Nonstop4h 44m

Toronto Pearson Intl

Wed 17/9

8:40 a.m.-10:59 a.m.

Nonstop5h 19m

C$ 362

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Tue 19/8

2:05 p.m.-12:46 a.m.

1 stop7h 41m

Toronto Region of Waterloo Intl

Fri 22/8

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

1 stop9h 58m

C$ 380

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Tue 9/9

7:16 a.m.-3:00 p.m.

Nonstop4h 44m

Toronto Pearson Intl

Sat 20/9

4:45 p.m.-7:08 p.m.

Nonstop5h 23m

C$ 405

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 10/9

8:40 a.m.-7:07 p.m.

1 stop7h 27m

London

Wed 17/9

6:00 a.m.-12:59 p.m.

1 stop9h 59m

C$ 405

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Tue 19/8

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

1 stop7h 36m

Hamilton

Fri 22/8

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

1 stop9h 58m

C$ 406

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Wed 10/9

7:15 p.m.-5:30 a.m.

3 stops31h 15m

Toronto Region of Waterloo Intl

Wed 17/9

6:30 a.m.-10:16 p.m.

2 stops18h 46m

C$ 420

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Thu 18/9

7:05 a.m.-6:20 p.m.

1 stop8h 15m

Ottawa

Sun 21/9

3:45 p.m.-8:29 p.m.

1 stop7h 44m

C$ 455

Flights are sorted by cheapest round-trip flights first.

Deals found on 28/7

Showing 1-10 of 47 results
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Best time to book a flight from Seattle to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Seattle 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 Seattle to Ontario

What is the cheapest month to book a flight from Seattle to Region of Ontario?

Currently, January is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of C$ 167). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 258). 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 SEA to ON?

Find hourly flight availability from Seattle to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 29 July 2025.

When flying from Seattle to Region of Ontario, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from Seattle to Region of Ontario

Explore weekly flight availability from Seattle to Ontario. 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 29 July 2025.

The most flights from SEA to CAON are scheduled on a Tuesday (7 on average). You will have fewer flight options on Friday, which is when the least amount of flights are scheduled (4 on average).

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. 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 Ontario. Reviews last updated 29 July 2025.
Check out reviews from past customers who have flown with Alaska Airlines,Delta, andUnited Airlines from Seattle to Ontario 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

Entertainment

7.1

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
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

Entertainment

7.1

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,977 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Entertainment

7.1

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,899 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Entertainment

7.1

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
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

Entertainment

7.1

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
WestJet
7.2
Good
2,973 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Boarding

8.1

Overall

8.0

Entertainment

7.1

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Ontario. 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 from for flights from Seattle to Ontario?

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

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

    The cheapest airlines for a one-way flight from Seattle to Region of Ontario are WestJet (C$ 161), Air Canada (C$ 162), and Alaska Airlines (C$ 167).

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

    When deciding which route to take from Seattle to Region of Ontario consider Seattle/Tacoma Intl - Toronto Pearson Intl, Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl or Seattle/Tacoma Intl - Hamilton as they are the most popular.

  • What are the most reliable airlines from Seattle to Region of Ontario?

    Consider Qatar Airways (97%), Alaska Airlines (92%) or Hawaiian Airlines (92%) when booking your flight. These represent the most reliable airlines when flying from Seattle to Region of Ontario.

  • What are the cheapest flights from Seattle to Region of Ontario?

    The cheapest flight price from Seattle to Region of Ontario is C$ 175. On average you can expect to pay C$ 706. The most popular route, (Seattle/Tacoma Intl - Toronto Pearson Intl), can usually be booked for C$ 318.

  • Can I find deals for flights from Seattle to Ontario that include hotel bookings?

    Yes. In addition to deals on Seattle to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Ontario.

  • Can I find deals for business class flights from Seattle to Ontario?

    Yes. Cheapflights offers flight deals from Seattle to Ontario 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 Seattle to Region of Ontario?

    Currently, January is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of C$ 167). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 258). 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

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Alternative routes for Seattle to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
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Top 3 airlines flying from Seattle to Ontario

Discover the top 3 airlines that operate flights from Seattle to Ontario. 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 29 July 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 189AverageC$ 574FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
WestJetCheapestC$ 295AverageC$ 478FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 418AverageC$ 721FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights

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

Cheapflights goes through 900+ travel sites to look for the best flight deals for flights from Seattle to Ontario. Too many options? Cheapflights also provides filters for things like airlines, price ranges, and number of stops to help you make a decision easily.

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

Cheapflights simply makes it quick and affordable to book flights from Seattle to Ontario by bringing together all flight options from hundreds of airlines and agencies online — and put it in one place for you to choose from. Plus, Cheapflights is 100% free to use for all.

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

Users can book flights with no change fees policies with our dedicated filters. Book flights from Seattle to Ontario flexibly with Cheapflights today.

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

Yes, and it’s super simple to set up. Click the bell icon next to the flight deals above and provide a valid email address to enable Price Alerts. That’s it!

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