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$117+ Cheap flights from Seattle (SEA) to Ontario

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 8/26. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
ago. 3 — ago. 101
dom. 8/3
dom. 8/10
1 adult, Economy
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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 julio 29, 2025.

Round-trip from

$243
(iWofly)

One-way from

$117
(Kiwi.com)

Popular in

June

Cheapest in

January

Average price

$490

Good round-trip deal

$464 or less

Good one-way deal

$207 or less
From Seattle/Tacoma Intl to Ontario
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One-way flight from Seattle/Tacoma Intl to Ontario
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Highest demand for flights based on searches. 13% potential increase in price ($63 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($9 potential savings vs. average RT price).
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Average for round-trip flights in July 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 julio 29, 2025.

This iWofly deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure iWofly is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 9/121:15 pmSEA - YYZ
1 stop8h 16mWestJet
vie. 9/1912:00 pmYYZ - SEA
2 stops11h 29mWestJet
Deal found 7/29$243
This Flightnetwork deal was found by Cheapflights users on 7/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 9/115:30 amSEA - YTZ
2 stops10h 15mAir Canada
jue. 9/184:10 pmYTZ - SEA
2 stops9h 06mAir Canada
Deal found 7/28$249
This Air Canada deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 9/912:00 pmSEA - YYZ
Nonstop4h 44mAir Canada
mié. 9/178:40 amYYZ - SEA
Nonstop5h 19mAir Canada
Deal found 7/29$267
This Trip.com deal was found by Cheapflights users on 7/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 8/192:05 pmSEA - YKF
1 stop7h 41mWestJet
vie. 8/226:00 amYKF - SEA
1 stop9h 58mWestJet
Deal found 7/26$277
This Trip.com deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 9/127:16 amSEA - YYZ
Nonstop4h 44mMultiple Airlines
vie. 9/193:00 pmYYZ - SEA
1 stop8h 29mMultiple Airlines
Deal found 7/29$293
This Priceline deal was found by Cheapflights users on 7/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 9/108:40 amSEA - YXU
1 stop7h 27mWestJet
mié. 9/176:00 amYXU - SEA
1 stop9h 59mWestJet
Deal found 7/27$295
This Trip.com deal was found by Cheapflights users on 7/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 8/192:05 pmSEA - YHM
1 stop7h 36mWestJet
vie. 8/226:00 amYHM - SEA
1 stop9h 58mWestJet
Deal found 7/26$296
This Mytrip deal was found by Cheapflights users on 7/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 9/107:15 pmSEA - YKF
3 stops31h 15mMultiple Airlines
mié. 9/176:30 amYKF - SEA
2 stops18h 46mMultiple Airlines
Deal found 7/27$306
This oojo deal was found by Cheapflights users on 7/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 9/108:40 amSEA - YOW
2 stops12h 42mWestJet
mié. 9/173:45 pmYOW - SEA
1 stop7h 44mWestJet
Deal found 7/27$338
This Gotogate deal was found by Cheapflights users on 7/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 8/257:35 pmSEA - YQT
1 stop20h 20mWestJet
lun. 9/17:40 pmYQT - SEA
1 stop20h 19mWestJet
Deal found 7/28$341
This Air Canada deal was found by Cheapflights users on 7/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 9/107:15 pmSEA - YXU
2 stops11h 04mAir Canada
mié. 9/176:10 amYXU - SEA
1 stop7h 49mAir Canada
Deal found 7/27$342
This Mytrip deal was found by Cheapflights users on 7/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 9/115:30 amSEA - YTZ
2 stops12h 11mMultiple Airlines
jue. 9/185:30 pmYTZ - SEA
3 stops18h 52mMultiple Airlines
Deal found 7/28$343

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 2,558,603 searches. Data last updated julio 29, 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

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

vie. 9/12

1:15 pm-12:31 am

1 stop8h 16m

Toronto Pearson Intl

vie. 9/19

12:00 pm-8:29 pm

2 stops11h 29m

$243

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

jue. 9/11

5:30 am-6:45 pm

2 stops10h 15m

Toronto Island

jue. 9/18

4:10 pm-10:16 pm

2 stops9h 06m

$249

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

mar. 9/9

2:55 pm-1:06 am

1 stop7h 11m

Toronto Pearson Intl

mié. 9/17

8:40 am-10:59 am

Nonstop5h 19m

$267

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

mar. 8/19

2:05 pm-12:46 am

1 stop7h 41m

Toronto Region of Waterloo Intl

vie. 8/22

6:00 am-12:58 pm

1 stop9h 58m

$277

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

vie. 9/12

7:16 am-3:00 pm

Nonstop4h 44m

Toronto Pearson Intl

vie. 9/19

3:00 pm-8:29 pm

1 stop8h 29m

$293

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

mié. 9/10

8:40 am-7:07 pm

1 stop7h 27m

London

mié. 9/17

6:00 am-12:59 pm

1 stop9h 59m

$295

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

mar. 8/19

2:05 pm-12:41 am

1 stop7h 36m

Hamilton

vie. 8/22

6:00 am-12:58 pm

1 stop9h 58m

$296

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

mié. 9/10

7:15 pm-5:30 am

3 stops31h 15m

Toronto Region of Waterloo Intl

mié. 9/17

6:30 am-10:16 pm

2 stops18h 46m

$306

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

jue. 9/18

7:05 am-6:20 pm

1 stop8h 15m

Ottawa

dom. 9/21

3:45 pm-8:29 pm

1 stop7h 44m

$332

SeattleThunder Bay

SEA - YQT

SEAYQT

Seattle/Tacoma Intl

lun. 8/25

7:35 pm-6:55 pm

1 stop20h 20m

Thunder Bay

lun. 9/1

7:40 pm-12:59 pm

1 stop20h 19m

$341

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Showing 1-10 of 50 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 $243). Flying from Seattle to Region of Ontario in August is currently the most expensive (average of $348). 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 julio 29, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to Region of Ontario as you normally would.

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 julio 29, 2025.

The most flights from SEA to CAON are scheduled on a Thursday (8 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (6 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 julio 29, 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 stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,979 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,896 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
WestJet
7.2
Good
2,972 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

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?

    For a flight from Seattle to Ontario, you will be flying from Seattle/Tacoma Intl. Seattle/Tacoma Intl (SEA) is just 11.4 mi from the center of the city.

  • What are the cheapest airlines to fly from Seattle to Region of Ontario one-way?

    To fly one-way, consider booking your trip with WestJet, which is currently one of the cheapest options available, starting at $117. Air Canada flights start at $118 while deals on Alaska Airlines start at $122 one-way.

  • What are the most popular routes from Seattle to Region of Ontario?

    The most popular route from Seattle to Region of Ontario is Seattle/Tacoma Intl - Toronto Pearson Intl. You may also consider Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl or Seattle/Tacoma Intl - Toronto Island.

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

    The top 3 most reliable airlines when flying from Seattle to Region of Ontario are Qatar Airways (97%), Alaska Airlines (92%) and Hawaiian Airlines (92%).

  • What are the cheapest flights from Seattle to Region of Ontario?

    Looking for the cheapest flight from Seattle to Region of Ontario? While on average our users pay $1,543, our data indicates the cheapest price to be $128. The most popular route (Seattle/Tacoma Intl - Toronto Pearson Intl), is priced around $242.

  • 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 $243). Flying from Seattle to Region of Ontario in August is currently the most expensive (average of $348). 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 5 airlines flying from Seattle to Ontario

Discover the top 5 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 2,558,603 searches. Data last updated julio 29, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$128Average$553FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$158Average$569FlexibilityNo cancel feeOn-time69%
DeltaCheapest$186Average$447FlexibilityNo cancel feeOn-timeN/A
WestJetCheapest$236Average$351FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$273Average$486FlexibilityNo cancel feeOn-time75%

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