Find flights
Deals
When to book
Airlines
FAQs

Cheap flights from Seattle to Ontario from C$ 188

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 6/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
30 Mar — 6 Apr1
1 adult

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 25 March 2025.

Round-trip from

C$ 355

One-way from

C$ 188

Popular in

April

Cheapest in

January

Average price

C$ 529

Good round-trip deal

C$ 438 or less

Good one-way deal

C$ 239 or less
WestJet
  • WestJet
  • 15/4-22/4
  • 3 total stops
  • 24h 13m total
  • Seattle to Ontario
Search Deals
6/5
  • 6/5
  • 2 total stops
  • 33h 11m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 9% potential increase in price (C$ 89 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 23 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 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

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 25 March 2025.

Tue 15/412:30 p.m.SEA - YYZ
2 stops14h 47mMultiple Airlines
Tue 22/47:55 a.m.YYZ - SEA
1 stop9h 26mMultiple Airlines
Deal found 24/3C$ 355
Thu 15/51:50 p.m.SEA - YKF
1 stop12h 25mMultiple Airlines
Mon 19/56:00 a.m.YKF - SEA
1 stop9h 58mMultiple Airlines
Deal found 24/3C$ 387
Mon 5/52:05 p.m.SEA - YKF
1 stop7h 41mWestJet
Tue 6/56:00 a.m.YKF - SEA
1 stop9h 58mWestJet
Deal found 24/3C$ 411
Sat 2/81:50 p.m.SEA - YYZ
1 stop7h 34mWestJet
Wed 13/88:00 a.m.YYZ - SEA
1 stop7h 58mWestJet
Deal found 24/3C$ 418
Thu 8/55:40 a.m.SEA - YTZ
2 stops9h 57mAir Canada
Thu 15/510:20 a.m.YTZ - SEA
2 stops12h 17mAir Canada
Deal found 24/3C$ 420
Fri 27/61:50 p.m.SEA - YHM
1 stop7h 51mWestJet
Mon 30/66:00 a.m.YHM - SEA
1 stop9h 58mWestJet
Deal found 23/3C$ 423
Tue 6/512:30 p.m.SEA - YHM
2 stops33h 11mMultiple Airlines
Tue 13/56:00 a.m.YHM - SEA
1 stop9h 58mMultiple Airlines
Deal found 23/3C$ 431
Tue 6/52:05 p.m.SEA - YOW
1 stop7h 36mWestJet
Tue 13/56:00 a.m.YOW - SEA
1 stop9h 58mWestJet
Deal found 24/3C$ 443
Wed 7/511:40 a.m.SEA - YYZ
Nonstop4h 57mAir Canada
Wed 14/58:30 a.m.YYZ - SEA
Nonstop5h 21mAir Canada
Deal found 24/3C$ 446
Tue 6/57:05 a.m.SEA - YOW
2 stops10h 56mMultiple Airlines
Tue 13/53:35 p.m.YOW - SEA
1 stop7h 53mMultiple Airlines
Deal found 24/3C$ 464
Mon 14/72:05 p.m.SEA - YUL
1 stop7h 38mWestJet
Tue 22/77:00 a.m.YUL - SEA
1 stop8h 58mWestJet
Deal found 23/3C$ 466
Wed 14/56:00 a.m.SEA - YTZ
3 stops31h 27mMultiple Airlines
Fri 16/57:00 a.m.YTZ - SEA
2 stops20h 10mMultiple Airlines
Deal found 24/3C$ 493

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 25 March 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

Tue 15/4

12:30 p.m.-6:17 a.m.

2 stops14h 47m

Toronto Pearson Intl

Tue 22/4

7:55 a.m.-2:21 p.m.

1 stop9h 26m

C$ 355

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Thu 15/5

1:50 p.m.-5:15 a.m.

1 stop12h 25m

Toronto Region of Waterloo Intl

Mon 19/5

6:00 a.m.-12:58 p.m.

1 stop9h 58m

C$ 387

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Wed 7/5

5:40 a.m.-8:37 p.m.

2 stops11h 57m

Toronto Island

Wed 14/5

10:20 a.m.-7:37 p.m.

2 stops12h 17m

C$ 408

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Tue 6/5

12:30 p.m.-12:41 a.m.

2 stops33h 11m

Hamilton

Mon 12/5

6:00 a.m.-2:25 p.m.

2 stops35h 25m

C$ 408

SeattleToronto

SEA - YKF

SEAYKF

Seattle/Tacoma Intl

Mon 5/5

2:05 p.m.-12:46 a.m.

1 stop7h 41m

Toronto Region of Waterloo Intl

Tue 6/5

6:00 a.m.-12:58 p.m.

1 stop9h 58m

C$ 411

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Sat 2/8

1:50 p.m.-12:24 a.m.

1 stop7h 34m

Toronto Pearson Intl

Wed 13/8

8:00 a.m.-12:58 p.m.

1 stop7h 58m

C$ 418

SeattleHamilton

SEA - YHM

SEAYHM

Seattle/Tacoma Intl

Fri 27/6

1:50 p.m.-12:41 a.m.

1 stop7h 51m

Hamilton

Mon 30/6

6:00 a.m.-12:58 p.m.

1 stop9h 58m

C$ 423

SeattleOttawa

SEA - YOW

SEAYOW

Seattle/Tacoma Intl

Tue 6/5

2:05 p.m.-12:41 a.m.

1 stop7h 36m

Ottawa

Tue 13/5

6:00 a.m.-12:58 p.m.

1 stop9h 58m

C$ 443

SeattleToronto

SEA - YYZ

SEAYYZ

Seattle/Tacoma Intl

Wed 7/5

11:40 a.m.-7:37 p.m.

Nonstop4h 57m

Toronto Pearson Intl

Wed 14/5

8:30 a.m.-10:51 a.m.

Nonstop5h 21m

C$ 446

SeattleToronto

SEA - YTZ

SEAYTZ

Seattle/Tacoma Intl

Wed 7/5

3:20 p.m.-11:32 a.m.

3 stops17h 12m

Toronto Island

Wed 14/5

10:20 a.m.-7:37 p.m.

2 stops12h 17m

C$ 461

Flights are sorted by cheapest round-trip flights first.

Deals found on 23/3

Showing 1-10 of 60 results
1
2
3
...
6

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 C$ 167). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 258). 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 25 March 2025.

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.

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 51.0 - 83.0 mm per month. June is typically the wettest month, when rainfall can reach 83.0 mm. February is typically the driest time to visit Region of Ontario when rainfall is around 51.0 mm.

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 21.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around -6.0 C).

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 25 March 2025.
Read through reviews of airlines operating flights from Seattle to Ontario, such as Alaska Airlines, Delta and Hawaiian 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
9,782 reviews
Check prices

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Food

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
9,782 reviews
Alaska Airlines
8.0
Very good
9,782 reviews
Check prices

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Food

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
7,890 reviews
Alaska Airlines
8.0
Very good
9,782 reviews
Check prices

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Food

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 😥
Hawaiian Airlines
7.9
Good
2,330 reviews
Alaska Airlines
8.0
Very good
9,782 reviews
Check prices

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Food

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
8,605 reviews
Alaska Airlines
8.0
Very good
9,782 reviews
Check prices

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Food

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
9,782 reviews
Check prices

Boarding

8.2

Entertainment

7.1

Comfort

7.9

Food

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?

    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.

  • 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 WestJet (C$ 199), Delta (C$ 219), and Alaska Airlines (C$ 231).

  • 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 - Montreal Pierre Elliott Trudeau Intl, Seattle/Tacoma Intl - Toronto Pearson Intl or Seattle/Tacoma Intl - Toronto Region of Waterloo Intl as they are the most popular.

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

    Consider Air Tahiti Nui (100%), Alaska Airlines (90%) or Hawaiian Airlines (90%) 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$ 222. On average you can expect to pay C$ 599. The most popular route, (Seattle/Tacoma Intl - Montreal Pierre Elliott Trudeau Intl), can usually be booked for C$ 481.

  • 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 C$ 167). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of C$ 258). 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Seattle to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Pierre Elliott Trudeau Intl flights
Seattle to Pearson Intl flights
Seattle to Vancouver Intl flights
Portland to Vancouver Intl flights
Seattle to Calgary flights
Portland to Pearson Intl flights
Seattle to Region of Waterloo Intl flights
Portland to Pierre Elliott Trudeau Intl flights
Seattle to Québec City flights
Seattle to Hamilton flights
Portland to Calgary flights
Seattle to Edmonton flights
Seattle to Kelowna flights
Portland to Edmonton flights
Seattle to Victoria flights
Seattle to Ottawa flights
Spokane to Vancouver Intl flights
Portland to Victoria flights
Spokane to Pearson Intl flights
Seattle to Halifax flights
Seattle to Winnipeg flights
Seattle to Fort McMurray flights
Spokane to Calgary flights
Portland to Ottawa flights
Portland to Halifax flights
Seattle to St. John's flights
Seattle to Kamloops flights
Seattle to Campbell River flights
Pasco to Pierre Elliott Trudeau Intl flights
Portland to Nanaimo flights
Pasco to Vancouver Intl flights
Seattle to London flights
Portland to Winnipeg flights
Seattle to Yellowknife flights
Pasco to Pearson Intl flights
Portland to Saskatoon flights
Portland to Sydney flights
Seattle to Regina flights
Portland to Whitehorse flights
Portland to Charlottetown flights
Portland to Williams Lake flights
Seattle to Grande Prairie flights
Portland to Regina flights
Portland to Fredericton flights
Seattle to Saskatoon flights

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 25 March 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 233AverageC$ 844FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
WestJetCheapestC$ 308AverageC$ 432FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Alaska AirlinesCheapestC$ 396AverageC$ 704FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines 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!

100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.