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Cheap flights from Seattle to Ontario from C$ 221

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 6/9. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
12 Jul — 19 Jul1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Seattle to Ontario

Enter your travel dates to find the best prices.

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 2026.

Sat 25/710:30 a.m.
SEA
-
YYZ
2 stops10h 29m
WestJet
Sun 2/812:00 p.m.
YYZ
-
SEA
2 stops12h 00m
WestJet
Deal found 11/6C$ 514
Thu 2/77:00 a.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Tue 14/71:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 9/6C$ 517
Mon 31/810:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Sun 6/93:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Deal found 11/6C$ 518
Wed 8/77:00 a.m.
SEA
-
YYZ
2 stops9h 00m
WestJet
Thu 16/72:50 p.m.
YYZ
-
SEA
1 stop9h 10m
WestJet
Deal found 12/6C$ 521
Tue 7/77:35 p.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Tue 14/71:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 9/6C$ 522
Thu 2/77:00 a.m.
SEA
-
YYZ
2 stops11h 10m
WestJet
Thu 9/73:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Deal found 10/6C$ 524
Fri 24/77:35 p.m.
SEA
-
YYZ
1 stop8h 20m
WestJet
Mon 3/81:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 11/6C$ 525
Thu 16/710:30 a.m.
SEA
-
YYZ
1 stop7h 45m
WestJet
Mon 20/73:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Deal found 11/6C$ 527
Wed 7/107:35 p.m.
SEA
-
YYZ
1 stop7h 10m
WestJet
Sat 17/101:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 10/6C$ 528
Sun 23/87:00 a.m.
SEA
-
YYZ
2 stops11h 10m
WestJet
Fri 4/91:30 p.m.
YYZ
-
SEA
1 stop8h 15m
WestJet
Deal found 9/6C$ 529
Thu 2/710:30 a.m.
SEA
-
YYZ
2 stops10h 29m
WestJet
Wed 8/73:50 p.m.
YYZ
-
SEA
1 stop8h 10m
WestJet
Deal found 10/6C$ 531
Sun 4/107:35 p.m.
SEA
-
YUL
1 stop8h 30m
WestJet
Sat 10/106:45 a.m.
YUL
-
SEA
2 stops15h 00m
WestJet
Deal found 8/6C$ 535

Find 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 2026.

Round-trip from

C$ 514

One-way from

C$ 221

Popular in

July

Cheapest in

January

Average price

C$ 698

Good round-trip deal

C$ 894 or less

Good one-way deal

C$ 339 or less
WestJet
  • WestJet
  • 25/7-2/8
  • 4 total stops
  • 22h 29m total
  • Seattle to Ontario
Search Deals
WestJet
  • WestJet
  • 6/9
  • 2 total stops
  • 10h 29m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 22% potential increase in price (C$ 215 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (C$ 22 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
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 629,999 searches. Data last updated 12 June 2026.
Use the filters below to find and compare flights from Seattle to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Sun 19/7

7:00 a.m.-7:50 p.m.

1 stop9h 50m

Toronto Region of Waterloo Intl

Sun 26/7

8:40 p.m.-9:40 a.m.

1 stop16h 00m

C$ 594

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Wed 16/9

7:35 p.m.-7:05 a.m.

1 stop8h 30m

Montreal Pierre Elliott Trudeau Intl

Wed 23/9

6:45 a.m.-6:45 p.m.

2 stops15h 00m

C$ 609

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Thu 16/7

7:00 a.m.-5:15 p.m.

1 stop7h 15m

Hamilton

Mon 20/7

6:10 p.m.-9:40 a.m.

1 stop18h 30m

C$ 617

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Sun 26/7

7:00 a.m.-5:15 p.m.

1 stop7h 15m

Hamilton

Sun 2/8

6:10 p.m.-9:00 p.m.

1 stop29h 50m

C$ 622

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Thu 24/9

7:35 p.m.-7:05 a.m.

1 stop8h 30m

Montreal Pierre Elliott Trudeau Intl

Tue 29/9

8:00 p.m.-6:45 p.m.

1 stop25h 45m

C$ 631

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Sun 30/8

7:00 a.m.-5:15 p.m.

1 stop7h 15m

Ottawa

Sat 5/9

1:20 p.m.-9:00 p.m.

1 stop10h 40m

C$ 631

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Sat 15/8

7:35 p.m.-7:05 a.m.

1 stop8h 30m

Montreal Pierre Elliott Trudeau Intl

Sat 22/8

7:15 a.m.-9:40 a.m.

1 stop29h 25m

C$ 638
Quickest round-trip

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Thu 17/9

8:00 a.m.-3:50 p.m.

Nonstop4h 50m

Toronto Pearson Intl

Sun 20/9

7:30 a.m.-2:28 p.m.

1 stop9h 58m

C$ 650

SeattleMontreal

SEA - YUL

SEAYUL

Seattle/Tacoma Intl

Mon 16/11

7:05 p.m.-7:10 a.m.

2 stops9h 05m

Montreal Pierre Elliott Trudeau Intl

Sun 22/11

3:10 p.m.-8:54 p.m.

1 stop8h 44m

C$ 665

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Mon 28/9

5:21 p.m.-10:06 a.m.

2 stops13h 45m

Toronto Island

Wed 30/9

7:20 p.m.-9:36 a.m.

1 stop17h 16m

C$ 665

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/6

Showing 1-10 of 60 resultsSorted by cheapest first
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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, November is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of C$ 123). Flying from Seattle to Region of Ontario in May is currently the most expensive (average of C$ 222). 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 2026.

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 2026.

The most flights from SEA to CAON are scheduled on a Wednesday (5 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (3 on average).

How much does it cost to fly round-trip from Seattle to Region of Ontario?

How far ahead should I book a flight from Seattle to Region of Ontario?

The price you pay for your flight from Seattle to Region of Ontario may vary depending on when you book. For the best chance of a lower fare, look to book 64 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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 2026.
Check out reviews from past customers who have flown with Alaska Airlines,WestJet, andAir Canada from Seattle to Ontario to help guide your decision. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
7.9
Good
12,499 reviews
Check prices

Overall

7.9

Comfort

7.8

Crew

8.5

Food

7.0

Entertainment

7.0

Boarding

8.1

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2026

SEA - RNO

There was a delay and my husband needs a wheelchair and we were moved from 1 gate to another.
Alaska Airlines
7.9
Good
12,499 reviews
Alaska Airlines
7.9
Good
12,499 reviews
Check prices

Overall

7.9

Comfort

7.8

Crew

8.5

Food

7.0

Entertainment

7.0

Boarding

8.1

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2026

SEA - RNO

There was a delay and my husband needs a wheelchair and we were moved from 1 gate to another.
WestJet
7.2
Good
3,357 reviews
Alaska Airlines
7.9
Good
12,499 reviews
Check prices

Overall

7.9

Comfort

7.8

Crew

8.5

Food

7.0

Entertainment

7.0

Boarding

8.1

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2026

SEA - RNO

There was a delay and my husband needs a wheelchair and we were moved from 1 gate to another.
Air Canada
7.1
Good
11,172 reviews
Alaska Airlines
7.9
Good
12,499 reviews
Check prices

Overall

7.9

Comfort

7.8

Crew

8.5

Food

7.0

Entertainment

7.0

Boarding

8.1

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2026

SEA - RNO

There was a delay and my husband needs a wheelchair and we were moved from 1 gate to another.

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.

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

    There are many flights that can get you from Seattle to Region of Ontario in 4h 50m. Fly via WestJet, United Airlines, or Alaska Airlines to get the fastest option. Airlines will cover a distance of 3306 km. Both multi-stop and direct flights can be found to your destination and back.

  • 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 Alaska Airlines (C$ 127), Air Canada (C$ 134), and WestJet (C$ 141).

  • 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 - Toronto Island or Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl as they are the most popular.

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

    Consider Air Canada (95%), United Airlines (95%) or Brussels Airlines (94%) 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$ 245. On average you can expect to pay C$ 716. The most popular route, (Seattle/Tacoma Intl - Toronto Pearson Intl), can usually be booked for C$ 525.

  • 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, November is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of C$ 123). Flying from Seattle to Region of Ontario in May is currently the most expensive (average of C$ 222). 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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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 2026.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 288AverageC$ 407FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 309AverageC$ 793FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Air CanadaCheapestC$ 369AverageC$ 462FlexibilityNo cancel feeOn-time67%
Search Air Canada 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.

Can Cheapflights notify me if prices for flights from Seattle to Ontario become cheaper?

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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