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Cheap flights from Seattle to Ontario from C$ 239

SEA — YYZ
21 Nov — 28 Nov1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Seattle to Ontario

Enter your travel dates to find the best prices.

Cheapest flights from Seattle to Ontario

Tue 17/112:30 p.m. -
2 stops12h 15m
Tue 24/117:30 a.m. -
1 stop9h 10m
Deal found 21/10C$ 514
Thu 24/122:30 p.m. -
2 stops12h 15m
Thu 31/126:10 a.m. -
1 stop10h 30m
Deal found 21/10C$ 517
Sat 31/103:20 p.m. -
1 stop11h 40m
Thu 5/116:10 a.m. -
1 stop10h 30m
Deal found 18/10C$ 519
Mon 21/122:30 p.m. -
2 stops12h 15m
Tue 5/17:30 a.m. -
1 stop9h 10m
Deal found 21/10C$ 524
Thu 3/122:30 p.m. -
2 stops12h 15m
Wed 9/127:30 a.m. -
1 stop9h 10m
Deal found 21/10C$ 527
Sun 6/122:30 p.m. -
2 stops12h 15m
Tue 8/127:30 a.m. -
1 stop9h 10m
Deal found 17/10C$ 528
Tue 1/122:30 p.m. -
2 stops12h 15m
Tue 8/127:30 a.m. -
1 stop9h 10m
Deal found 17/10C$ 531
Fri 11/122:30 p.m. -
2 stops12h 15m
Mon 14/127:30 a.m. -
1 stop9h 10m
Deal found 21/10C$ 533
Tue 24/112:30 p.m. -
2 stops12h 15m
Tue 1/127:30 a.m. -
1 stop9h 10m
Deal found 19/10C$ 535
Sat 28/112:20 p.m. -
2 stops12h 25m
Tue 1/127:30 a.m. -
1 stop9h 10m
Deal found 19/10C$ 538
Sat 12/122:20 p.m. -
2 stops12h 25m
Tue 15/127:30 a.m. -
1 stop9h 10m
Deal found 20/10C$ 540
Tue 24/112:30 p.m. -
2 stops12h 15m
Mon 30/1110:20 p.m. -
1 stop18h 20m
Deal found 21/10C$ 541

Find flight deals from Seattle to Ontario

Round-trip from

C$ 514

One-way from

C$ 239

Popular in

July

Cheapest in

January

Average price

C$ 848

Good round-trip deal

C$ 324 or less

Good one-way deal

C$ 301 or less
WestJet
  • WestJet
  • 17/11-24/11
  • 3 total stops
  • 21h 25m total
  • Seattle to Ontario
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WestJet
  • WestJet
  • 24/11-31/12
  • 2 total stops
  • 12h 15m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 21% potential increase in price (C$ 243 potential increase over avg. RT price).
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Cheapest flight prices on average. 4% potential price decrease (C$ 42 potential savings vs. average RT price).
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Average for round-trip flights in October 2026
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to Ontario.
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to Ontario.
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Cheapflights Fare Finder

 
Use the filters below to find and compare flights from Seattle to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Wed 25/11

8:31 a.m.-4:05 p.m.

Nonstop4h 34m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 302

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Tue 24/11

8:31 a.m.-4:05 p.m.

Nonstop4h 34m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 302
Quickest round-trip

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Sat 5/12

8:33 a.m.-4:05 p.m.

Nonstop4h 32m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 302

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Wed 6/1

8:29 a.m.-4:05 p.m.

Nonstop4h 36m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 302

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Wed 18/11

11:15 p.m.-8:55 a.m.

1 stop6h 40m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 316

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Tue 17/11

10:40 p.m.-11:09 a.m.

1 stop9h 29m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 316

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Sun 22/11

8:31 a.m.-4:05 p.m.

Nonstop4h 34m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 318

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Fri 27/11

8:31 a.m.-4:05 p.m.

Nonstop4h 34m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 318

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Fri 20/11

8:31 a.m.-4:05 p.m.

Nonstop4h 34m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 318

SeattleToronto

SEA Seattle/Tacoma Intl - YYZ Toronto Pearson Intl

SEAYYZ

Seattle/Tacoma Intl

Thu 19/11

11:45 a.m.-10:51 p.m.

1 stop8h 06m

Toronto Pearson Intl

Wed 31/12

12:00 a.m.-9:00 p.m.

Nonstop0h 00m

C$ 330

Flights are sorted by cheapest round-trip flights first.

Deals found on 22/10

Showing 1-10 of 57 resultsSorted by cheapest first
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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

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$ 385). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 849). 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?

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.

How much does it cost to fly round-trip from Seattle to Region of Ontario?

Airfare is typical for this route at the moment.
Seattle to Region of Ontario flights typically cost between C$ 457 and C$ 914 in November.
The cheapest round-trip price found within the last 5 days was C$ 514 on WestJet (17 Nov-24 Nov).

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

The price you pay for your flight from Seattle to Region of Ontario may vary depending on when you book. For the best chance of a lower fare, look to book 64 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

Reviews of airlines servicing Ontario

Check out reviews from past customers who have flown with Alaska Airlines,WestJet, andAir Canada 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
7.9
Good
13,103 reviews
Check prices

Overall

7.9

Entertainment

7.0

Comfort

7.8

Food

7.0

Boarding

8.1

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle
Alaska Airlines
7.9
Good
13,103 reviews
Alaska Airlines
7.9
Good
13,103 reviews
Check prices

Overall

7.9

Entertainment

7.0

Comfort

7.8

Food

7.0

Boarding

8.1

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle
WestJet
7.2
Good
3,447 reviews
Alaska Airlines
7.9
Good
13,103 reviews
Check prices

Overall

7.9

Entertainment

7.0

Comfort

7.8

Food

7.0

Boarding

8.1

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle
Air Canada
7.1
Good
11,790 reviews
Alaska Airlines
7.9
Good
13,103 reviews
Check prices

Overall

7.9

Entertainment

7.0

Comfort

7.8

Food

7.0

Boarding

8.1

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle

Related info for your journey

  • 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.

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

    There are many flights that can get you from Seattle to Region of Ontario in 4h 46m. Fly via WestJet, Alaska Airlines, or Delta to get the fastest option. Airlines will cover a distance of 3306 km. Both multi-stop and direct flights can be found to your destination and back.

  • 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 Alaska Airlines (C$ 123), Air Canada (C$ 140), and WestJet (C$ 151).

  • 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 - Toronto Island or Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl as they are the most popular.

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

    Consider Qatar Airways (100%), Alaska Airlines (100%) or Air Canada (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$ 252. On average you can expect to pay C$ 598. The most popular route, (Seattle/Tacoma Intl - Toronto Pearson Intl), can usually be booked for C$ 590.

  • 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$ 385). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 849). 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

Browse thousands of different options on Cheapflights for your next trip

Top 3 airlines flying from Seattle to Ontario

AirlineCheapestAverageFlexibilityOn-time
Alaska AirlinesCheapestC$ 317AverageC$ 785FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
WestJetCheapestC$ 357AverageC$ 569FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Air CanadaCheapestC$ 371AverageC$ 758FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

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