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$86+ 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 10/1. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
Oct 11 — Oct 181
Sat 10/11
Sat 10/18
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 September 11, 2025.

Round-trip from

$223
(oojo)

One-way from

$86
(oojo)

Popular in

June

Cheapest in

January

Average price

$408

Good round-trip deal

$398 or less

Good one-way deal

$154 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. 14% potential increase in price ($65 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
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Average for round-trip flights in September 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 September 11, 2025.

This oojo deal was found by Cheapflights users on 9/9. 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.
Wed 10/11:50 pmSEA - YHM
1 stop7h 50mWestJet
Mon 10/66:00 amYHM - SEA
1 stop17h 29mWestJet
Deal found 9/9$223
This Trip.com deal was found by Cheapflights users on 9/10. 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.
Sat 10/181:50 pmSEA - YHM
1 stop7h 50mWestJet
Sat 10/256:00 amYHM - SEA
1 stop9h 59mWestJet
Deal found 9/10$242
This oojo deal was found by Cheapflights users on 9/9. 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.
Fri 10/241:50 pmSEA - YHM
1 stop7h 50mWestJet
Sun 10/266:10 pmYHM - SEA
1 stop23h 10mWestJet
Deal found 9/9$245
This oojo deal was found by Cheapflights users on 9/9. 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.
Fri 10/178:40 amSEA - YOW
2 stops12h 42mWestJet
Mon 10/206:00 amYOW - SEA
1 stop9h 59mWestJet
Deal found 9/9$247
This Trip.com deal was found by Cheapflights users on 9/10. 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.
Mon 10/202:05 pmSEA - YHM
1 stop7h 35mWestJet
Thu 10/236:00 amYHM - SEA
1 stop9h 59mWestJet
Deal found 9/10$251
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/118:40 amSEA - YYZ
1 stop7h 12mWestJet
Sat 10/181:30 pmYYZ - SEA
1 stop8h 51mWestJet
Deal found 9/10$253
This Kiwi.com deal was found by Cheapflights users on 9/9. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/111:55 amSEA - YYZ
2 stops8h 44mMultiple Airlines
Sun 11/164:45 pmYYZ - SEA
Nonstop5h 20mMultiple Airlines
Deal found 9/9$254
This Kiwi.com deal was found by Cheapflights users on 9/9. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/311:55 amSEA - YYZ
1 stop16h 03mMultiple Airlines
Sat 11/154:45 pmYYZ - SEA
Nonstop5h 20mMultiple Airlines
Deal found 9/9$255
This Trip.com deal was found by Cheapflights users on 9/11. 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.
Mon 10/202:05 pmSEA - YYZ
1 stop7h 17mWestJet
Thu 10/236:30 amYYZ - SEA
1 stop9h 29mWestJet
Deal found 9/11$256
This Trip.com deal was found by Cheapflights users on 9/11. 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.
Thu 10/161:50 pmSEA - YHM
1 stop7h 50mWestJet
Tue 10/216:00 amYHM - SEA
1 stop9h 59mWestJet
Deal found 9/11$256
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/151:02 pmSEA - YYZ
2 stops14h 10mMultiple Airlines
Mon 10/208:00 amYYZ - SEA
1 stop7h 59mMultiple Airlines
Deal found 9/10$257
This oojo deal was found by Cheapflights users on 9/10. 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.
Fri 11/283:10 pmSEA - YKF
1 stop11h 18mWestJet
Mon 12/16:20 amYKF - SEA
1 stop11h 00mWestJet
Deal found 9/10$257

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 September 11, 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

Wed 10/1

1:50 pm-12:40 am

1 stop7h 50m

Hamilton

Mon 10/6

6:00 am-8:29 pm

1 stop17h 29m

$223

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sat 10/18

1:50 pm-12:40 am

1 stop7h 50m

Hamilton

Sat 10/25

6:00 am-12:59 pm

1 stop9h 59m

$242

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Fri 10/24

1:50 pm-12:40 am

1 stop7h 50m

Hamilton

Sun 10/26

6:10 pm-2:20 pm

1 stop23h 10m

$245

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Fri 10/17

8:40 am-12:22 am

2 stops12h 42m

Ottawa

Mon 10/20

6:00 am-12:59 pm

1 stop9h 59m

$247

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Mon 10/20

2:05 pm-12:40 am

1 stop7h 35m

Hamilton

Thu 10/23

6:00 am-12:59 pm

1 stop9h 59m

$256

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Thu 10/16

1:50 pm-12:40 am

1 stop7h 50m

Hamilton

Tue 10/21

6:00 am-12:59 pm

1 stop9h 59m

$256

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Fri 11/28

3:10 pm-5:28 am

1 stop11h 18m

Toronto Region of Waterloo Intl

Mon 12/1

6:20 am-2:20 pm

1 stop11h 00m

$257

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Wed 10/8

1:50 pm-12:40 am

1 stop7h 50m

Ottawa

Thu 10/23

6:00 am-12:59 pm

1 stop9h 59m

$261

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Tue 10/21

7:05 am-6:20 pm

1 stop8h 15m

Ottawa

Thu 10/23

6:00 am-12:59 pm

1 stop9h 59m

$261

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Sun 10/19

7:18 am-3:00 pm

Nonstop4h 42m

Toronto Pearson Intl

Sat 11/1

4:45 pm-7:05 pm

Nonstop5h 20m

$262

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/9

Showing 1-10 of 60 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 September 11, 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 September 11, 2025.

The most flights from SEA to CAON are scheduled on a Monday (7 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (5 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 September 11, 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

Food

7.1

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

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

Food

7.1

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

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
7,960 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

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
8,937 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

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
3,091 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

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.
Air Canada
7.1
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

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.

  • How long is the flight from Seattle to Region of Ontario?

    Departing from Seattle to Region of Ontario will take you 4h 42m. The distance between Seattle and Region of Ontario is about 2054 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • 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 $99. Air Canada flights start at $118 while deals on United Airlines start at $127 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 - Hamilton.

  • 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 (98%), Alaska Airlines (95%) and Hawaiian Airlines (95%).

  • 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 $414, our data indicates the cheapest price to be $132. The most popular route (Seattle/Tacoma Intl - Toronto Pearson Intl), is priced around $210.

  • 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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Portland to Whitehorse flights

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 September 11, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$128Average$557FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$160Average$518FlexibilityNo cancel feeOn-time69%
DeltaCheapest$186Average$427FlexibilityNo cancel feeOn-timeN/A
WestJetCheapest$235Average$353FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$276Average$504FlexibilityNo cancel feeOn-time75%

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