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$94+ 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 12/11. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
dic. 13 — dic. 201
sáb. 12/13
sáb. 12/20
1 adult, Economy
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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 noviembre 13, 2025.

This Kiwi.com deal was found by Cheapflights users on 11/10. 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.
mar. 12/23:10 pmSEA - YYZ
2 stops12h 48mMultiple Airlines
mié. 12/34:45 pmYYZ - SEA
Nonstop5h 33mMultiple Airlines
Deal found 11/10$251
This Trip.com deal was found by Cheapflights users on 11/10. 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.
mar. 12/23:10 pmSEA - YYZ
2 stops12h 48mWestJet
mié. 12/310:15 pmYYZ - SEA
1 stop19h 05mWestJet
Deal found 11/10$252
This Trip.com deal was found by Cheapflights users on 11/12. 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.
mié. 12/103:10 pmSEA - YYZ
2 stops11h 48mWestJet
jue. 12/118:45 pmYYZ - SEA
1 stop16h 37mWestJet
Deal found 11/12$255
This Trip.com deal was found by Cheapflights users on 11/10. 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.
vie. 12/53:10 pmSEA - YYZ
2 stops12h 48mWestJet
lun. 12/86:30 pmYYZ - SEA
2 stops22h 50mWestJet
Deal found 11/10$257
This Kiwi.com deal was found by Cheapflights users on 11/13. 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.
sáb. 11/2911:55 amSEA - YYZ
2 stops8h 44mWestJet
mié. 12/310:15 pmYYZ - SEA
1 stop19h 05mWestJet
Deal found 11/13$258
This Kiwi.com deal was found by Cheapflights users on 11/10. 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.
jue. 11/273:10 pmSEA - YYZ
2 stops12h 48mWestJet
mar. 12/27:45 amYYZ - SEA
1 stop9h 35mWestJet
Deal found 11/10$260
This Kiwi.com deal was found by Cheapflights users on 11/13. 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.
jue. 12/1111:01 amSEA - YYZ
1 stop8h 59mMultiple Airlines
jue. 12/187:55 pmYYZ - SEA
1 stop17h 16mMultiple Airlines
Deal found 11/13$261
This Kiwi.com deal was found by Cheapflights users on 11/11. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 12/33:15 pmSEA - YYZ
1 stop28h 56mWestJet
dom. 12/77:45 amYYZ - SEA
1 stop9h 35mWestJet
Deal found 11/11$263
This Kiwi.com deal was found by Cheapflights users on 11/11. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 11/2211:55 amSEA - YYZ
2 stops8h 44mWestJet
vie. 12/58:45 pmYYZ - SEA
1 stop16h 37mWestJet
Deal found 11/11$264
This Kiwi.com deal was found by Cheapflights users on 11/10. 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.
jue. 12/43:10 pmSEA - YYZ
1 stop18h 18mWestJet
lun. 12/87:45 amYYZ - SEA
1 stop9h 35mWestJet
Deal found 11/10$265
This Kiwi.com deal was found by Cheapflights users on 11/11. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 12/43:10 pmSEA - YYZ
2 stops12h 48mWestJet
dom. 12/77:45 amYYZ - SEA
1 stop9h 35mWestJet
Deal found 11/11$266
This Kiwi.com deal was found by Cheapflights users on 11/10. 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.
vie. 12/511:55 amSEA - YYZ
2 stops15h 03mWestJet
dom. 12/77:45 amYYZ - SEA
1 stop9h 35mWestJet
Deal found 11/10$268

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 noviembre 13, 2025.

Most accurate provider

Mytrip
3 stars

Most trusted provider

Mytrip
3 stars

Round-trip from

$251
(Alaska Airlines)

One-way from

$94
(Trip.com)

Popular in

June

Cheapest in

February

Average price

$292

Good round-trip deal

$331 or less

Good one-way deal

$262 or less
Provider with most accurate pricing for Seattle/Tacoma Intl-Toronto (YTO) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Toronto (YTO) flights.
Search Deals
From Seattle/Tacoma Intl to Ontario
Search Deals
One-way flight from Seattle/Tacoma Intl to Ontario
Search Deals
Highest demand for flights based on searches. 15% potential increase in price ($72 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in November 2025
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 2,558,603 searches. Data last updated noviembre 13, 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 - YKF

SEAYKF

Seattle/Tacoma Intl

dom. 3/22

3:10 pm-5:29 am

1 stop11h 19m

Toronto Region of Waterloo Intl

sáb. 3/28

7:00 pm-2:19 pm

1 stop22h 19m

$263

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

mar. 2/24

7:55 am-3:35 pm

Nonstop4h 40m

Toronto Pearson Intl

sáb. 2/28

4:45 pm-7:18 pm

Nonstop5h 33m

$272

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

mié. 1/14

7:55 am-3:35 pm

Nonstop4h 40m

Toronto Pearson Intl

dom. 1/18

4:45 pm-7:17 pm

Nonstop5h 32m

$272

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

dom. 2/22

7:55 am-3:35 pm

Nonstop4h 40m

Toronto Pearson Intl

jue. 2/26

4:45 pm-7:18 pm

Nonstop5h 33m

$272

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

dom. 2/22

7:55 am-3:35 pm

Nonstop4h 40m

Toronto Pearson Intl

lun. 2/23

4:45 pm-7:18 pm

Nonstop5h 33m

$272

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

jue. 4/30

2:05 pm-12:42 am

1 stop7h 37m

Montreal Pierre Elliott Trudeau Intl

dom. 5/3

6:45 am-8:28 pm

1 stop16h 43m

$277

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

vie. 1/23

3:10 pm-12:42 am

2 stops30h 32m

Ottawa

lun. 1/26

5:40 am-2:20 pm

2 stops11h 40m

$280

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

jue. 1/22

3:10 pm-6:21 pm

2 stops24h 11m

Ottawa

lun. 1/26

5:45 pm-2:20 pm

1 stop23h 35m

$288

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

mar. 5/5

7:05 am-7:07 pm

1 stop9h 02m

London

mié. 5/6

8:00 pm-8:28 pm

1 stop27h 28m

$291

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

jue. 3/12

7:55 am-3:35 pm

Nonstop4h 40m

Toronto Pearson Intl

vie. 3/13

4:45 pm-7:18 pm

Nonstop5h 33m

$294

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/12

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, March is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of $121). Flying from Seattle to Region of Ontario in May is currently the most expensive (average of $271). 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 noviembre 13, 2025.

When flying from Seattle to Region of Ontario, the time of day you fly usually plays a role in the price. Save by searching for a flight in the afternoon, which can drop the price by up to 50% versus a flight in the morning.

What is the cheapest day to fly from Seattle to Region of Ontario?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Ontario. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Seattle to Region of Ontario flight should consider departing on Wednesday evenings when fares are most often at their lowest. Sunday evenings flights should be avoided if possible as fares are typically the most expensive at this time.

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 noviembre 13, 2025.

The most flights from SEA to CAON are scheduled on a Monday (6 on average). You will have fewer flight options on Friday, which is when the least amount of flights are scheduled (2 on average).

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 noviembre 13, 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
11,281 reviews

Comfort

7.8

Entertainment

7.0

Boarding

8.1

Overall

8.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Alaska Airlines
8.0
Very good
11,281 reviews
Alaska Airlines
8.0
Very good
11,281 reviews

Comfort

7.8

Entertainment

7.0

Boarding

8.1

Overall

8.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Delta
7.9
Good
8,007 reviews
Alaska Airlines
8.0
Very good
11,281 reviews

Comfort

7.8

Entertainment

7.0

Boarding

8.1

Overall

8.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
United Airlines
7.4
Good
9,015 reviews
Alaska Airlines
8.0
Very good
11,281 reviews

Comfort

7.8

Entertainment

7.0

Boarding

8.1

Overall

8.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
WestJet
7.2
Good
3,159 reviews
Alaska Airlines
8.0
Very good
11,281 reviews

Comfort

7.8

Entertainment

7.0

Boarding

8.1

Overall

8.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Air Canada
7.1
Good
10,444 reviews
Alaska Airlines
8.0
Very good
11,281 reviews

Comfort

7.8

Entertainment

7.0

Boarding

8.1

Overall

8.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.

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 40m. 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 $94. Alaska Airlines flights start at $101 while deals on Air Canada start at $143 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 - Toronto Island or Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl.

  • 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 Alaska Airlines (98%), Qatar Airways (97%) and Hawaiian Airlines (96%).

  • 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 $704, our data indicates the cheapest price to be $111. The most popular route (Seattle/Tacoma Intl - Toronto Pearson Intl), is priced around $214.

  • 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, March is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of $121). Flying from Seattle to Region of Ontario in May is currently the most expensive (average of $271). 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.

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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 noviembre 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$165Average$553FlexibilityNo cancel feeOn-time67%
DeltaCheapest$182Average$427FlexibilityNo cancel feeOn-timeN/A
WestJetCheapest$222Average$351FlexibilityNo cancel feeOn-time60%
Alaska AirlinesCheapest$253Average$473FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$282Average$489FlexibilityNo cancel feeOn-time69%

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