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$55+ 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 6/16. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
May 5 — May 121
Mon 5/5
Mon 5/12
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 April 30, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$199
(Flightnetwork)

One-way from

$55
(Vakatrip)

Popular in

June

Cheapest in

January

Average price

$493

Good round-trip deal

$394 or less

Good one-way deal

$209 or less
Provider with most accurate pricing for Seattle/Tacoma Intl-Toronto (YTO) flight deals.
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Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Toronto (YTO) flights.
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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 ($7 potential savings vs. average RT price).
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Average for round-trip flights in April 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 April 30, 2025.

This Flightnetwork deal was found by Cheapflights users on 4/28. 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.
Thu 6/122:55 pmSEA - YXU
3 stops15h 23mAir Canada
Thu 6/199:55 amYXU - SEA
2 stops13h 46mAir Canada
Deal found 4/28$199
This Flightnetwork deal was found by Cheapflights users on 4/28. 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.
Thu 6/1211:35 amSEA - YQT
1 stop8h 14mAir Canada
Thu 6/195:15 amYQT - SEA
1 stop8h 36mAir Canada
Deal found 4/28$207
This Trip.com deal was found by Cheapflights users on 4/29. 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.
Thu 5/291:50 pmSEA - YHM
1 stop7h 51mWestJet
Wed 6/46:00 amYHM - SEA
1 stop9h 58mWestJet
Deal found 4/29$237
This Mytrip deal was found by Cheapflights users on 4/28. 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.
Thu 6/127:05 amSEA - YXU
1 stop19h 09mMultiple Airlines
Thu 6/196:15 amYXU - SEA
1 stop7h 36mMultiple Airlines
Deal found 4/28$242
This Trip.com deal was found by Cheapflights users on 4/29. 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.
Wed 7/161:50 pmSEA - YKF
1 stop7h 56mWestJet
Sun 7/206:00 amYKF - SEA
1 stop17h 28mWestJet
Deal found 4/29$258
This Flightnetwork deal was found by Cheapflights users on 4/29. 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/35:30 amSEA - YTZ
2 stops10h 07mAir Canada
Tue 6/2410:20 amYTZ - SEA
2 stops13h 21mAir Canada
Deal found 4/29$280
This United Airlines deal was found by Cheapflights users on 4/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/3111:50 pmSEA - YXU
2 stops18h 38mUnited Airlines
Sat 6/79:55 amYXU - SEA
2 stops15h 25mUnited Airlines
Deal found 4/28$290
This United Airlines deal was found by Cheapflights users on 4/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/1211:50 pmSEA - YQT
2 stops19h 59mUnited Airlines
Thu 6/195:15 amYQT - SEA
2 stops22h 44mUnited Airlines
Deal found 4/28$293
This Mytrip deal was found by Cheapflights users on 4/29. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/33:20 pmSEA - YYZ
3 stops30h 13mMultiple Airlines
Tue 6/242:00 pmYYZ - SEA
1 stop9h 41mMultiple Airlines
Deal found 4/29$296
This Kiwi.com deal was found by Cheapflights users on 4/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/117:05 amSEA - YKF
2 stops19h 25mMultiple Airlines
Wed 6/186:00 amYKF - SEA
1 stop9h 58mMultiple Airlines
Deal found 4/28$301
This Flightnetwork deal was found by Cheapflights users on 4/29. 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/42:55 pmSEA - YYZ
1 stop7h 14mAir Canada
Tue 6/108:30 amYYZ - SEA
Nonstop5h 21mAir Canada
Deal found 4/29$303
This Alaska Airlines deal was found by Cheapflights users on 4/28. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/287:23 amSEA - YYZ
Nonstop4h 37mAlaska Airlines
Tue 6/34:45 pmYYZ - SEA
Nonstop5h 19mAlaska Airlines
Deal found 4/28$307

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 April 30, 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

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 6/12

2:55 pm-9:18 am

3 stops15h 23m

London

Thu 6/19

9:55 am-8:41 pm

2 stops13h 46m

$199

SeattleThunder Bay

SEA - YQT

SEAYQT

Seattle/Tacoma Intl

Thu 6/12

11:35 am-10:49 pm

1 stop8h 14m

Thunder Bay

Thu 6/19

5:15 am-10:51 am

1 stop8h 36m

$207

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Thu 5/29

1:50 pm-12:41 am

1 stop7h 51m

Hamilton

Wed 6/4

6:00 am-12:58 pm

1 stop9h 58m

$237

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 6/12

7:05 am-5:14 am

1 stop19h 09m

London

Thu 6/19

6:15 am-10:51 am

1 stop7h 36m

$242

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Wed 7/16

1:50 pm-12:46 am

1 stop7h 56m

Toronto Region of Waterloo Intl

Sun 7/20

6:00 am-8:28 pm

1 stop17h 28m

$258

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Tue 6/3

5:30 am-6:37 pm

2 stops10h 07m

Toronto Island

Tue 6/24

10:20 am-8:41 pm

2 stops13h 21m

$280

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 5/31

11:50 pm-9:28 pm

2 stops18h 38m

London

Sat 6/7

9:55 am-10:20 pm

2 stops15h 25m

$290

SeattleThunder Bay

SEA - YQT

SEAYQT

Seattle/Tacoma Intl

Thu 6/12

11:50 pm-10:49 pm

2 stops19h 59m

Thunder Bay

Thu 6/19

5:15 am-12:59 am

2 stops22h 44m

$293

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Tue 6/3

3:20 pm-12:33 am

3 stops30h 13m

Toronto Pearson Intl

Tue 6/24

2:00 pm-8:41 pm

1 stop9h 41m

$296

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Wed 6/11

7:05 am-5:30 am

2 stops19h 25m

Toronto Region of Waterloo Intl

Wed 6/18

6:00 am-12:58 pm

1 stop9h 58m

$301

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/29

Showing 1-10 of 58 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 July is currently the most expensive (average of $359). 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 April 30, 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 April 30, 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 (2 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 2.0 - 3.3 inches per month. June is typically the wettest month, when rainfall can reach 3.3 in. February is typically the driest time to visit Region of Ontario when rainfall is around 2.0 in.

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 69.8 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 21.2 F).

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 April 30, 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
9,961 reviews

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Alaska Airlines
8.0
Very good
9,961 reviews
Alaska Airlines
8.0
Very good
9,961 reviews

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Delta
8.0
Very good
7,929 reviews
Alaska Airlines
8.0
Very good
9,961 reviews

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
United Airlines
7.4
Good
8,696 reviews
Alaska Airlines
8.0
Very good
9,961 reviews

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
9,961 reviews

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
WestJet
7.2
Good
2,823 reviews
Alaska Airlines
8.0
Very good
9,961 reviews

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥

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 $55. Air Canada flights start at $105 while deals on United Airlines start at $146 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 Brussels Airlines (100%), Air Tahiti Nui (95%) and Alaska Airlines (90%).

  • 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 $502, our data indicates the cheapest price to be $159. The most popular route (Seattle/Tacoma Intl - Toronto Pearson Intl), is priced around $260.

  • 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 July is currently the most expensive (average of $359). 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 April 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$136Average$468FlexibilityNo cancel feeOn-time67%
WestJetCheapest$145Average$426FlexibilityNo cancel feeOn-time60%
United AirlinesCheapest$158Average$489FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$251Average$492FlexibilityNo cancel feeOn-time75%
DeltaCheapest$394Average$513FlexibilityNo cancel feeOn-timeN/A

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