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Cheap flights from Seattle to Ontario from C$ 148

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 18/7. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
17 Jun — 24 Jun1
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 12 June 2025.

Round-trip from

C$ 324

One-way from

C$ 148

Popular in

June

Cheapest in

January

Average price

C$ 718

Good round-trip deal

C$ 511 or less

Good one-way deal

C$ 275 or less
WestJet
  • WestJet
  • 3/8-18/8
  • 2 total stops
  • 17h 34m total
  • Seattle to Ontario
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WestJet
  • WestJet
  • 18/7
  • 1 total stop
  • 7h 51m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 13% potential increase in price (C$ 122 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 20 potential savings vs. average RT price).
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Average for round-trip flights in June 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 12 June 2025.

Sun 3/82:05 p.m.SEA - YHM
1 stop7h 36mWestJet
Mon 18/86:00 a.m.YHM - SEA
1 stop9h 58mWestJet
Deal found 10/6C$ 324
Thu 17/77:35 p.m.SEA - YXU
1 stop6h 39mWestJet
Tue 22/76:00 a.m.YXU - SEA
1 stop9h 58mWestJet
Deal found 10/6C$ 349
Fri 25/78:40 a.m.SEA - YYZ
2 stops12h 53mWestJet
Tue 29/79:00 a.m.YYZ - SEA
2 stops13h 14mWestJet
Deal found 10/6C$ 383
Thu 31/71:50 p.m.SEA - YKF
1 stop7h 56mWestJet
Thu 7/87:45 p.m.YKF - SEA
2 stops19h 46mWestJet
Deal found 11/6C$ 383
Tue 15/77:17 a.m.SEA - YYZ
Nonstop4h 43mAlaska Airlines
Fri 18/74:45 p.m.YYZ - SEA
Nonstop5h 24mAlaska Airlines
Deal found 10/6C$ 391
Fri 26/97:15 a.m.SEA - YTZ
1 stop9h 34mAir Canada
Tue 30/912:25 p.m.YTZ - SEA
1 stop10h 06mAir Canada
Deal found 12/6C$ 396
Fri 7/112:07 p.m.SEA - YYZ
1 stop6h 52mUnited Airlines
Fri 14/115:55 p.m.YYZ - SEA
1 stop10h 04mUnited Airlines
Deal found 10/6C$ 412
Mon 4/82:55 p.m.SEA - YYZ
2 stops12h 14mAir Canada
Mon 18/86:15 a.m.YYZ - SEA
2 stops11h 01mAir Canada
Deal found 12/6C$ 413
Fri 17/103:39 p.m.SEA - YKF
2 stops10h 36mMultiple Airlines
Mon 20/106:00 a.m.YKF - SEA
1 stop9h 59mMultiple Airlines
Deal found 10/6C$ 413
Mon 4/87:05 a.m.SEA - YYZ
1 stop7h 17mMultiple Airlines
Tue 19/84:45 p.m.YYZ - SEA
Nonstop5h 24mMultiple Airlines
Deal found 10/6C$ 416
Mon 14/77:15 p.m.SEA - YXU
2 stops11h 02mAir Canada
Sat 19/76:15 a.m.YXU - SEA
1 stop7h 45mAir Canada
Deal found 12/6C$ 417
Mon 3/111:24 a.m.SEA - YYZ
1 stop7h 56mAmerican Airlines
Wed 12/116:20 p.m.YYZ - SEA
1 stop7h 55mAmerican Airlines
Deal found 11/6C$ 428

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 12 June 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

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sun 3/8

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

1 stop7h 36m

Hamilton

Mon 18/8

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

1 stop9h 58m

C$ 324

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 17/7

7:35 p.m.-5:14 a.m.

1 stop6h 39m

London

Tue 22/7

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

1 stop9h 58m

C$ 349

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Fri 25/7

8:40 a.m.-12:33 a.m.

2 stops12h 53m

Toronto Pearson Intl

Tue 29/7

9:00 a.m.-7:14 p.m.

2 stops13h 14m

C$ 383

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Thu 31/7

1:50 p.m.-12:46 a.m.

1 stop7h 56m

Toronto Region of Waterloo Intl

Thu 7/8

7:45 p.m.-12:31 p.m.

2 stops19h 46m

C$ 383

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Tue 15/7

7:17 a.m.-3:00 p.m.

Nonstop4h 43m

Toronto Pearson Intl

Fri 18/7

4:45 p.m.-7:09 p.m.

Nonstop5h 24m

C$ 391

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Fri 5/9

7:15 a.m.-7:49 p.m.

1 stop9h 34m

Toronto Island

Sun 7/9

12:25 p.m.-7:31 p.m.

1 stop10h 06m

C$ 396

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Fri 7/11

2:07 p.m.-11:59 p.m.

1 stop6h 52m

Toronto Pearson Intl

Fri 14/11

5:55 p.m.-12:59 a.m.

1 stop10h 04m

C$ 412

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Mon 4/8

2:55 p.m.-6:09 a.m.

2 stops12h 14m

Toronto Pearson Intl

Mon 18/8

6:15 a.m.-2:16 p.m.

2 stops11h 01m

C$ 413

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Mon 4/8

7:35 p.m.-6:52 a.m.

1 stop8h 17m

Toronto Pearson Intl

Tue 19/8

4:45 p.m.-7:09 p.m.

Nonstop5h 24m

C$ 416

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Sat 16/8

4:50 p.m.-5:15 a.m.

1 stop9h 25m

Toronto Region of Waterloo Intl

Sun 24/8

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

1 stop9h 58m

C$ 416

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/6

Showing 1-10 of 59 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$ 255). 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 12 June 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 12 June 2025.

The most flights from SEA to CAON are scheduled on a Tuesday (6 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (4 on average).

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Region of Ontario ranges from 51.0 - 83.0 mm per month. June is typically the wettest month, when rainfall can reach 83.0 mm. February is typically the driest time to visit Region of Ontario when rainfall is around 51.0 mm.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Region of Ontario, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 21.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around -6.0 C).

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 12 June 2025.
Read through reviews of airlines operating flights from Seattle to Ontario, such as Alaska Airlines, Delta and United Airlines. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Surinder,May 2025

SEA - YYZ

My wife wanted the aile seat and I always prefer window seat. Luckily we both got the best seats we wanted. The plane was very nice and we enjoyed the best take off and the smooth landing at Toronto. All the services by the staff inside the aeroplane were very nice well appreciated. Thanks again and hope to see you soon.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Surinder,May 2025

SEA - YYZ

My wife wanted the aile seat and I always prefer window seat. Luckily we both got the best seats we wanted. The plane was very nice and we enjoyed the best take off and the smooth landing at Toronto. All the services by the staff inside the aeroplane were very nice well appreciated. Thanks again and hope to see you soon.
Delta
8.0
Very good
7,946 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Surinder,May 2025

SEA - YYZ

My wife wanted the aile seat and I always prefer window seat. Luckily we both got the best seats we wanted. The plane was very nice and we enjoyed the best take off and the smooth landing at Toronto. All the services by the staff inside the aeroplane were very nice well appreciated. Thanks again and hope to see you soon.
United Airlines
7.4
Good
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Surinder,May 2025

SEA - YYZ

My wife wanted the aile seat and I always prefer window seat. Luckily we both got the best seats we wanted. The plane was very nice and we enjoyed the best take off and the smooth landing at Toronto. All the services by the staff inside the aeroplane were very nice well appreciated. Thanks again and hope to see you soon.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Surinder,May 2025

SEA - YYZ

My wife wanted the aile seat and I always prefer window seat. Luckily we both got the best seats we wanted. The plane was very nice and we enjoyed the best take off and the smooth landing at Toronto. All the services by the staff inside the aeroplane were very nice well appreciated. Thanks again and hope to see you soon.
WestJet
7.2
Good
2,868 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Crew

8.5

Overall

8.0

Food

7.1

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Surinder,May 2025

SEA - YYZ

My wife wanted the aile seat and I always prefer window seat. Luckily we both got the best seats we wanted. The plane was very nice and we enjoyed the best take off and the smooth landing at Toronto. All the services by the staff inside the aeroplane were very nice well appreciated. Thanks again and hope to see you soon.

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$ 148), Air Canada (C$ 185), and United Airlines (C$ 189).

  • 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 - Toronto Island as they are the most popular.

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

    Consider Qatar Airways (93%), 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$ 183. On average you can expect to pay C$ 511. The most popular route, (Seattle/Tacoma Intl - Toronto Pearson Intl), can usually be booked for C$ 335.

  • 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$ 255). 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 12 June 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 189AverageC$ 701FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
WestJetCheapestC$ 294AverageC$ 490FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 388AverageC$ 681FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines 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.

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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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