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Cheap flights from Seattle to Ontario from C$ 134

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 21/4. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
10 Apr — 17 Apr1
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
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 11 March 2026.

Wed 27/58:00 a.m.
SEA
-
YYZ
Nonstop4h 50m
Air Canada
Tue 2/66:45 p.m.
YYZ
-
SEA
Nonstop5h 23m
Air Canada
Deal found 8/3C$ 319
Sat 18/48:00 a.m.
SEA
-
YYZ
Nonstop4h 54m
Air Canada
Sat 25/47:30 p.m.
YYZ
-
SEA
Nonstop5h 23m
Air Canada
Deal found 8/3C$ 331
Sat 25/48:00 a.m.
SEA
-
YYZ
Nonstop4h 54m
Air Canada
Fri 1/512:30 a.m.
YYZ
-
SEA
2 stops12h 20m
Air Canada
Deal found 9/3C$ 333
Thu 7/57:20 p.m.
SEA
-
YYZ
2 stops9h 50m
Air Canada
Sat 9/512:30 a.m.
YYZ
-
SEA
2 stops12h 20m
Air Canada
Deal found 9/3C$ 356
Tue 5/57:20 p.m.
SEA
-
YTZ
2 stops12h 07m
Air Canada
Mon 11/53:35 p.m.
YTZ
-
SEA
2 stops9h 45m
Air Canada
Deal found 10/3C$ 415
Wed 22/43:10 p.m.
SEA
-
YKF
1 stop11h 19m
WestJet
Wed 29/48:40 p.m.
YKF
-
SEA
1 stop16h 00m
WestJet
Deal found 7/3C$ 426
Sat 2/57:20 p.m.
SEA
-
YTZ
2 stops12h 07m
Air Canada
Tue 5/58:55 p.m.
YTZ
-
SEA
2 stops15h 55m
Air Canada
Deal found 8/3C$ 430
Wed 27/57:20 p.m.
SEA
-
YTZ
2 stops12h 07m
Air Canada
Tue 2/68:55 p.m.
YTZ
-
SEA
2 stops15h 55m
Air Canada
Deal found 8/3C$ 432
Thu 28/57:35 p.m.
SEA
-
YKF
1 stop21h 15m
WestJet
Sun 31/58:40 p.m.
YKF
-
SEA
1 stop16h 00m
WestJet
Deal found 8/3C$ 434
Wed 22/43:10 p.m.
SEA
-
YKF
1 stop11h 19m
WestJet
Mon 27/48:40 p.m.
YKF
-
SEA
1 stop16h 00m
WestJet
Deal found 10/3C$ 444
Tue 28/45:40 a.m.
SEA
-
YTZ
2 stops9h 42m
Air Canada
Sun 31/58:55 p.m.
YTZ
-
SEA
2 stops15h 55m
Air Canada
Deal found 7/3C$ 445
Thu 4/67:35 p.m.
SEA
-
YKF
1 stop21h 15m
WestJet
Mon 15/68:40 p.m.
YKF
-
SEA
1 stop16h 00m
WestJet
Deal found 8/3C$ 451

Find flight deals from Seattle to Ontario

Keep the following information in mind while searching for Seattle to Ontario flight deals. Data was last updated 11 March 2026.

Round-trip from

C$ 319

One-way from

C$ 134

Popular in

June

Cheapest in

January

Average price

C$ 543

Good round-trip deal

C$ 880 or less

Good one-way deal

C$ 135 or less
Air Canada
  • Air Canada
  • 27/5-2/6
  • Nonstop
  • 10h 13m total
  • Seattle to Ontario
Search Deals
Air Canada
  • Air Canada
  • 21/4
  • Nonstop
  • 4h 54m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 14% potential increase in price (C$ 114 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2026
Search Deals
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.
Search Deals

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 11 March 2026.
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 - YYZ

SEAYYZ

Seattle/Tacoma Intl

Sat 9/5

11:53 p.m.-9:54 a.m.

1 stop7h 01m

Toronto Pearson Intl

Tue 12/5

6:30 a.m.-12:25 p.m.

1 stop8h 55m

C$ 406

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Tue 31/3

11:59 p.m.-9:54 a.m.

1 stop6h 55m

Toronto Pearson Intl

Sat 4/4

3:53 p.m.-11:12 p.m.

1 stop10h 19m

C$ 418

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Mon 13/4

10:35 p.m.-9:54 a.m.

1 stop8h 19m

Toronto Pearson Intl

Fri 17/4

2:45 p.m.-12:34 a.m.

1 stop12h 49m

C$ 436

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Thu 4/6

9:10 a.m.-11:14 p.m.

1 stop11h 04m

Toronto Pearson Intl

Sun 7/6

1:30 p.m.-12:06 a.m.

1 stop13h 36m

C$ 439

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sun 10/5

7:35 p.m.-5:15 p.m.

1 stop18h 40m

Hamilton

Wed 13/5

6:10 p.m.-9:40 a.m.

1 stop18h 30m

C$ 467

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Thu 28/5

7:35 p.m.-7:50 p.m.

1 stop21h 15m

Toronto Region of Waterloo Intl

Tue 2/6

8:40 p.m.-9:40 a.m.

1 stop16h 00m

C$ 468
Quickest round-trip

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Thu 4/6

7:59 a.m.-3:45 p.m.

Nonstop4h 46m

Toronto Pearson Intl

Tue 9/6

4:55 p.m.-7:19 p.m.

Nonstop5h 24m

C$ 481

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Thu 4/6

7:35 p.m.-7:50 p.m.

1 stop21h 15m

Toronto Region of Waterloo Intl

Mon 22/6

8:40 p.m.-6:45 p.m.

1 stop25h 05m

C$ 482

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Thu 18/6

7:35 p.m.-7:50 p.m.

1 stop21h 15m

Toronto Region of Waterloo Intl

Sun 21/6

8:40 p.m.-6:45 p.m.

1 stop25h 05m

C$ 486

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Thu 21/5

10:30 a.m.-5:15 p.m.

1 stop27h 45m

Hamilton

Sun 24/5

6:10 p.m.-6:45 p.m.

1 stop27h 35m

C$ 493

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/3

Showing 1-10 of 60 resultsSorted by cheapest first
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6

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$ 179). Flying from Seattle to Region of Ontario in December is currently the most expensive (average of C$ 382). 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 11 March 2026.

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 11 March 2026.

The most flights from SEA to CAON are scheduled on a Monday (8 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (3 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 11 March 2026.
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
8.0
Very good
12,027 reviews
Check prices

Boarding

8.1

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Overall

8.0

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
Alaska Airlines
8.0
Very good
12,027 reviews
Alaska Airlines
8.0
Very good
12,027 reviews
Check prices

Boarding

8.1

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Overall

8.0

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
WestJet
7.2
Good
3,290 reviews
Alaska Airlines
8.0
Very good
12,027 reviews
Check prices

Boarding

8.1

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Overall

8.0

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
Air Canada
7.1
Good
10,800 reviews
Alaska Airlines
8.0
Very good
12,027 reviews
Check prices

Boarding

8.1

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Overall

8.0

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.

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.

  • 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 7h 01m. Fly via United Airlines, Delta, or WestJet 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), WestJet (C$ 135), and Air Canada (C$ 135).

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

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

    Consider Alaska Airlines (87%), Hawaiian Airlines (87%) or Qatar Airways (87%) 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$ 127. On average you can expect to pay C$ 580. The most popular route, (Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl), can usually be booked for C$ 530.

  • 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$ 179). Flying from Seattle to Region of Ontario in December is currently the most expensive (average of C$ 382). 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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Portland to Fredericton flights
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Walla Walla to Pierre Elliott Trudeau Intl flights
Portland to Whitehorse flights
Portland to Saskatoon flights

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 11 March 2026.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 280AverageC$ 430FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 300AverageC$ 692FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Air CanadaCheapestC$ 358AverageC$ 454FlexibilityNo cancel feeOn-time67%
Search Air Canada 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 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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