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Cheap flights from Seattle to Ontario from C$ 248

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 23/8. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
26 Aug — 2 Sep1
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 July 2026.

Thu 24/97:35 p.m.
SEA
-
YOW
1 stop7h 00m
WestJet
Mon 28/912:25 p.m.
YOW
-
SEA
2 stops9h 20m
WestJet
Deal found 25/7C$ 488
Tue 15/97:35 p.m.
SEA
-
YOW
1 stop7h 00m
WestJet
Sat 26/91:20 p.m.
YOW
-
SEA
1 stop8h 25m
WestJet
Deal found 26/7C$ 520
Thu 27/810:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Mon 31/81:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 22/7C$ 538
Fri 28/810:30 a.m.
SEA
-
YYZ
2 stops10h 29m
WestJet
Sun 6/91:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 23/7C$ 541
Mon 28/97:35 p.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Wed 7/1010:20 p.m.
YYZ
-
SEA
2 stops14h 20m
WestJet
Deal found 23/7C$ 542
Wed 9/97:35 p.m.
SEA
-
YOW
1 stop7h 00m
WestJet
Sat 19/91:20 p.m.
YOW
-
SEA
1 stop8h 25m
WestJet
Deal found 27/7C$ 542
Tue 25/87:00 a.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Wed 2/93:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Deal found 24/7C$ 544
Sun 13/910:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Sat 10/1010:20 p.m.
YYZ
-
SEA
2 stops14h 20m
WestJet
Deal found 25/7C$ 545
Tue 11/810:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Fri 21/812:00 p.m.
YYZ
-
SEA
2 stops12h 00m
WestJet
Deal found 24/7C$ 547
Thu 20/87:00 a.m.
SEA
-
YYZ
2 stops11h 10m
WestJet
Mon 24/83:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Deal found 26/7C$ 548
Tue 11/810:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Sat 22/81:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 24/7C$ 550
Sun 6/97:00 a.m.
SEA
-
YYZ
2 stops11h 10m
WestJet
Mon 14/91:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 24/7C$ 551

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 July 2026.

Round-trip from

C$ 488

One-way from

C$ 248

Popular in

July

Cheapest in

January

Average price

C$ 912

Good round-trip deal

C$ 912 or less

Good one-way deal

C$ 443 or less
WestJet
  • WestJet
  • 24/9-28/9
  • 3 total stops
  • 16h 20m total
  • Seattle to Ontario
Search Deals
WestJet
  • WestJet
  • 23/8
  • 1 total stop
  • 7h 15m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 26% potential increase in price (C$ 297 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (C$ 44 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 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 July 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

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Thu 24/9

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

1 stop7h 00m

Ottawa

Mon 28/9

8:15 p.m.-9:40 a.m.

1 stop16h 25m

C$ 521

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Tue 11/8

7:00 a.m.-5:15 p.m.

1 stop7h 15m

Hamilton

Tue 25/8

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

1 stop18h 30m

C$ 566

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Fri 16/10

7:35 p.m.-7:05 a.m.

1 stop8h 30m

Montreal Pierre Elliott Trudeau Intl

Fri 23/10

5:30 p.m.-9:40 a.m.

1 stop19h 10m

C$ 571

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sun 23/8

7:00 a.m.-5:15 p.m.

1 stop7h 15m

Hamilton

Wed 26/8

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

1 stop18h 30m

C$ 582

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sun 23/8

7:00 a.m.-5:15 p.m.

1 stop7h 15m

Hamilton

Tue 25/8

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

1 stop18h 30m

C$ 582

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Sat 10/10

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

1 stop21h 15m

Toronto Region of Waterloo Intl

Mon 12/10

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

1 stop25h 05m

C$ 595

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Sat 3/10

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

1 stop21h 15m

Toronto Region of Waterloo Intl

Sun 11/10

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

1 stop16h 00m

C$ 596

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Fri 21/8

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

1 stop21h 15m

Toronto Region of Waterloo Intl

Wed 26/8

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

1 stop16h 00m

C$ 607

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Wed 9/9

9:43 a.m.-11:27 p.m.

1 stop10h 44m

Montreal Pierre Elliott Trudeau Intl

Sat 12/9

7:00 a.m.-4:45 p.m.

1 stop12h 45m

C$ 614

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Wed 16/9

11:35 a.m.-11:50 p.m.

1 stop9h 15m

Montreal Pierre Elliott Trudeau Intl

Tue 22/9

12:48 p.m.-6:45 p.m.

1 stop8h 57m

C$ 614

Flights are sorted by cheapest round-trip flights first.

Deals found on 26/7

Showing 1-10 of 60 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
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$ 386). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 845). 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 July 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 27 July 2026.

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

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

Airfare is below average for this route at the moment.
Seattle to Region of Ontario flights typically cost between C$ 548 and C$ 1,043 in August.
The cheapest round-trip price found within the last 5 days was C$ 538 on WestJet (27 Aug-31 Aug).

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 59 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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 July 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
7.9
Good
12,719 reviews
Check prices

Food

7.0

Entertainment

7.0

Comfort

7.8

Overall

7.9

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
12,719 reviews
Alaska Airlines
7.9
Good
12,719 reviews
Check prices

Food

7.0

Entertainment

7.0

Comfort

7.8

Overall

7.9

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
3,415 reviews
Alaska Airlines
7.9
Good
12,719 reviews
Check prices

Food

7.0

Entertainment

7.0

Comfort

7.8

Overall

7.9

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
11,392 reviews
Alaska Airlines
7.9
Good
12,719 reviews
Check prices

Food

7.0

Entertainment

7.0

Comfort

7.8

Overall

7.9

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

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 4h 45m. Fly via WestJet, Delta, or Alaska Airlines 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$ 130), Air Canada (C$ 140), and WestJet (C$ 146).

  • 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 - Hamilton as they are the most popular.

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

    Consider Air Canada (97%), United Airlines (97%) or Brussels Airlines (94%) 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$ 443. On average you can expect to pay C$ 871. The most popular route, (Seattle/Tacoma Intl - Toronto Pearson Intl), can usually be booked for C$ 527.

  • 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$ 386). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 845). 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 27 July 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 264AverageC$ 548FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
Alaska AirlinesCheapestC$ 287AverageC$ 787FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
WestJetCheapestC$ 291AverageC$ 447FlexibilityNo cancel feeOn-time60%
Search WestJet 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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