Find flights
Deals
When to book
Airlines
FAQs

Cheap flights from Seattle to Ontario from C$ 137

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 14/3. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
26 Feb — 5 Mar1
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 27 January 2026.

Sat 14/38:10 a.m.
SEA
-
YYZ
Nonstop4h 43m
Air Canada
Tue 17/38:00 a.m.
YYZ
-
SEA
2 stops10h 01m
Air Canada
Deal found 25/1C$ 305
Sat 28/28:00 a.m.
SEA
-
YYZ
Nonstop4h 43m
Air Canada
Sat 7/38:00 a.m.
YYZ
-
SEA
2 stops10h 01m
Air Canada
Deal found 27/1C$ 308
Sat 14/37:55 a.m.
SEA
-
YYZ
Nonstop4h 40m
Alaska Airlines
Tue 17/34:45 p.m.
YYZ
-
SEA
Nonstop5h 33m
Alaska Airlines
Deal found 25/1C$ 320
Sat 23/57:35 p.m.
SEA
-
YYZ
1 stop8h 20m
WestJet
Thu 4/61:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 27/1C$ 329
Mon 25/57:35 p.m.
SEA
-
YYZ
1 stop8h 20m
WestJet
Thu 4/61:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 27/1C$ 330
Wed 20/57:35 p.m.
SEA
-
YYZ
1 stop8h 20m
WestJet
Thu 4/61:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 27/1C$ 338
Sat 2/52:05 p.m.
SEA
-
YUL
1 stop7h 37m
WestJet
Sat 9/56:45 a.m.
YUL
-
SEA
1 stop9h 23m
WestJet
Deal found 24/1C$ 342
Sat 2/52:05 p.m.
SEA
-
YKF
1 stop7h 40m
WestJet
Sat 9/56:00 a.m.
YKF
-
SEA
1 stop10h 08m
WestJet
Deal found 24/1C$ 352
Fri 10/48:41 a.m.
SEA
-
YKF
2 stops17h 48m
Multiple Airlines
Thu 16/46:20 a.m.
YKF
-
SEA
1 stop10h 59m
Multiple Airlines
Deal found 27/1C$ 360
Tue 12/57:15 a.m.
SEA
-
YTZ
1 stop9h 37m
Air Canada
Sun 17/512:30 p.m.
YTZ
-
SEA
1 stop10h 07m
Air Canada
Deal found 25/1C$ 371
Sat 2/57:05 a.m.
SEA
-
YHM
1 stop7h 10m
WestJet
Sat 9/56:10 p.m.
YHM
-
SEA
1 stop21h 58m
WestJet
Deal found 24/1C$ 378
Fri 13/35:40 a.m.
SEA
-
YTZ
2 stops9h 30m
Air Canada
Fri 20/312:30 p.m.
YTZ
-
SEA
2 stops13h 26m
Air Canada
Deal found 27/1C$ 381

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 27 January 2026.

Round-trip from

C$ 305

One-way from

C$ 137

Popular in

June

Cheapest in

January

Average price

C$ 368

Good round-trip deal

C$ 321 or less

Good one-way deal

C$ 112 or less
Air Canada
  • Air Canada
  • 14/3-17/3
  • 2 total stops
  • 14h 44m total
  • Seattle to Ontario
Search Deals
Air Canada
  • Air Canada
  • 14/3
  • Nonstop
  • 4h 43m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (C$ 134 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 January 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 27 January 2026.
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

Sat 14/3

3:40 p.m.-5:38 a.m.

2 stops10h 58m

Toronto Pearson Intl

Tue 17/3

8:00 a.m.-3:01 p.m.

2 stops10h 01m

C$ 309

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Wed 18/2

8:00 a.m.-3:43 p.m.

Nonstop4h 43m

Toronto Pearson Intl

Wed 25/2

7:50 p.m.-10:16 p.m.

Nonstop5h 26m

C$ 345

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Sat 2/5

2:05 p.m.-12:45 a.m.

1 stop7h 40m

Toronto Region of Waterloo Intl

Sat 9/5

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

1 stop10h 08m

C$ 352

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Tue 12/5

7:15 a.m.-7:52 p.m.

1 stop9h 37m

Toronto Island

Sun 17/5

12:30 p.m.-7:37 p.m.

1 stop10h 07m

C$ 371

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sat 2/5

7:05 a.m.-5:15 p.m.

1 stop7h 10m

Hamilton

Sat 9/5

6:10 p.m.-1:08 p.m.

1 stop21h 58m

C$ 378

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Sat 28/2

8:00 a.m.-3:43 p.m.

Nonstop4h 43m

Toronto Pearson Intl

Sat 7/3

8:20 p.m.-8:31 a.m.

1 stop15h 11m

C$ 378

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Sat 28/2

11:59 p.m.-2:01 p.m.

1 stop11h 02m

Toronto Pearson Intl

Sat 7/3

10:51 a.m.-7:03 p.m.

1 stop11h 12m

C$ 379

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Fri 13/3

5:40 a.m.-6:10 p.m.

2 stops9h 30m

Toronto Island

Fri 20/3

12:30 p.m.-10:56 p.m.

2 stops13h 26m

C$ 381

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Fri 27/2

8:00 a.m.-3:43 p.m.

Nonstop4h 43m

Toronto Pearson Intl

Mon 2/3

5:55 p.m.-10:57 p.m.

1 stop8h 02m

C$ 382

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Wed 25/2

7:55 a.m.-3:35 p.m.

Nonstop4h 40m

Toronto Pearson Intl

Mon 2/3

4:45 p.m.-7:18 p.m.

Nonstop5h 33m

C$ 389

Flights are sorted by cheapest round-trip flights first.

Deals found on 26/1

Showing 1-10 of 60 results
1
2
3
...
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, April is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of C$ 171). Flying from Seattle to Region of Ontario in December is currently the most expensive (average of C$ 385). 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 27 January 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.

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

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 27 January 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
11,799 reviews
Check prices

Overall

8.0

Food

7.1

Crew

8.5

Entertainment

7.0

Boarding

8.1

Comfort

7.8

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
11,799 reviews
Alaska Airlines
8.0
Very good
11,799 reviews
Check prices

Overall

8.0

Food

7.1

Crew

8.5

Entertainment

7.0

Boarding

8.1

Comfort

7.8

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
3,251 reviews
Alaska Airlines
8.0
Very good
11,799 reviews
Check prices

Overall

8.0

Food

7.1

Crew

8.5

Entertainment

7.0

Boarding

8.1

Comfort

7.8

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
10,663 reviews
Alaska Airlines
8.0
Very good
11,799 reviews
Check prices

Overall

8.0

Food

7.1

Crew

8.5

Entertainment

7.0

Boarding

8.1

Comfort

7.8

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 40m. Fly via Air Canada, WestJet, or United Airlines to get the fastest option. Airlines will cover a distance of 3257 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 WestJet (C$ 136), Air Canada (C$ 136), and Alaska Airlines (C$ 152).

  • 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 Air Canada (85%), United Airlines (85%) or Alaska Airlines (83%) 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$ 112. On average you can expect to pay C$ 543. 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, April is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of C$ 171). Flying from Seattle to Region of Ontario in December is currently the most expensive (average of C$ 385). 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

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Seattle to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Vancouver Intl flights
Seattle to Pearson Intl flights
Portland to Vancouver Intl flights
Seattle to Calgary flights
Seattle to Kelowna flights
Seattle to Pierre Elliott Trudeau Intl flights
Portland to Calgary flights
Portland to Pearson Intl flights
Seattle to Hamilton flights
Portland to Pierre Elliott Trudeau Intl flights
Seattle to Edmonton flights
Spokane to Vancouver Intl flights
Seattle to Victoria flights
Seattle to Region of Waterloo Intl flights
Portland to Victoria flights
Seattle to Halifax flights
Portland to Edmonton flights
Seattle to Winnipeg flights
Seattle to Yellowknife flights
Pasco to Pearson Intl flights
Spokane to Calgary flights
Seattle to Ottawa flights
Seattle to Québec City flights
Seattle to St. John's flights
Portland to Ottawa flights
Pasco to Vancouver Intl flights
Spokane to Edmonton flights
Seattle to Saskatoon flights
Portland to Winnipeg flights
Portland to Nanaimo flights
Spokane to Pearson Intl flights
Seattle to Kamloops flights
Seattle to London flights
Seattle to Regina flights
Portland to Fredericton flights
Seattle to Campbell River flights
Spokane to Winnipeg flights
Spokane to Halifax flights
Portland to Charlottetown flights
Pasco to Pierre Elliott Trudeau Intl flights
Portland to Whitehorse flights
Portland to Saskatoon flights
Portland to Sydney flights
Portland to Halifax 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 27 January 2026.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 283AverageC$ 387FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 303AverageC$ 777FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Air CanadaCheapestC$ 361AverageC$ 523FlexibilityNo 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!

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.