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Cheap flights from Toronto Region of Waterloo Intl Airport to Seattle from C$ 240

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 23/10. Fares are subject to change and may not be available on all flights or dates of travel.
YKF — SEA
11 Oct — 18 Oct1
1 adult
1 adult, Economy

Cheap flight deals from Region of Waterloo Intl to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Region of Waterloo Intl (YKF) to Seattle (SEA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 11 September 2025.

Round-trip from

C$ 324

One-way from

C$ 240

Popular in

November

Cheapest in

May

Average price

C$ 263
WestJet
  • WestJet
  • 6/10-22/10
  • 2 total stops
  • 25h 24m total
  • Toronto to Seattle
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23/10
  • 23/10
  • 3 total stops
  • 19h 30m total
  • Toronto to Seattle
Search Deals
Highest demand for flights based on searches. 34% potential increase in price (C$ 311 potential increase over avg. RT price).
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Cheapest flight prices on average. 21% potential price decrease (C$ 107 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Region of Waterloo Intl to Seattle

Cheapest flights from Region of Waterloo Intl to Seattle
Explore the most affordable flight options available from Region of Waterloo Intl to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 11 September 2025.

Mon 6/106:00 a.m.YKF - SEA
1 stop17h 29mWestJet
Wed 22/101:50 p.m.SEA - YKF
1 stop7h 55mWestJet
Deal found 10/9C$ 324
Sat 25/106:00 a.m.YKF - SEA
1 stop9h 59mWestJet
Sun 2/113:10 p.m.SEA - YKF
1 stop11h 18mWestJet
Deal found 10/9C$ 333
Mon 3/116:20 a.m.YKF - SEA
1 stop11h 00mWestJet
Wed 12/113:10 p.m.SEA - YKF
1 stop11h 18mWestJet
Deal found 8/9C$ 376
Tue 11/116:20 a.m.YKF - SEA
1 stop11h 00mWestJet
Sun 16/113:10 p.m.SEA - YKF
1 stop11h 18mWestJet
Deal found 10/9C$ 381
Sun 12/106:15 a.m.YKF - SEA
1 stop9h 20mMultiple Airlines
Sat 18/108:40 a.m.SEA - YKF
2 stops17h 50mMultiple Airlines
Deal found 9/9C$ 387
Fri 17/106:00 a.m.YKF - SEA
1 stop9h 59mWestJet
Mon 20/102:05 p.m.SEA - YKF
1 stop7h 40mWestJet
Deal found 9/9C$ 389
Fri 26/96:15 a.m.YKF - SEA
1 stop9h 20mMultiple Airlines
Sun 28/98:40 a.m.SEA - YKF
1 stop17h 35mMultiple Airlines
Deal found 8/9C$ 423
Thu 16/106:00 a.m.YKF - SEA
1 stop9h 59mWestJet
Thu 23/101:50 p.m.SEA - YKF
1 stop7h 55mWestJet
Deal found 9/9C$ 432
Fri 17/106:00 a.m.YKF - SEA
1 stop9h 59mWestJet
Sun 19/108:40 a.m.SEA - YKF
1 stop13h 05mWestJet
Deal found 8/9C$ 509

Cheapflights Fare Finder

 
Customize your flight search to find flights from Region of Waterloo Intl to Seattle 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 11 September 2025.
Use the filters below to find and compare flights from Toronto Region of Waterloo Intl Airport to Seattle that are best for you.

Fly from

Region of Waterloo Intl

Fly to

Seattle

Route

Depart

Return

Price

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 6/10

6:00 a.m.-8:29 p.m.

1 stop17h 29m

Seattle/Tacoma Intl

Wed 22/10

1:50 p.m.-12:45 a.m.

1 stop7h 55m

C$ 324

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 3/11

6:20 a.m.-2:20 p.m.

1 stop11h 00m

Seattle/Tacoma Intl

Wed 12/11

3:10 p.m.-5:28 a.m.

1 stop11h 18m

C$ 376

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Sun 12/10

6:15 a.m.-12:35 p.m.

1 stop9h 20m

Seattle/Tacoma Intl

Sat 18/10

8:40 a.m.-5:30 a.m.

2 stops17h 50m

C$ 387

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 26/9

6:15 a.m.-12:35 p.m.

1 stop9h 20m

Seattle/Tacoma Intl

Sun 28/9

8:40 a.m.-5:15 a.m.

1 stop17h 35m

C$ 423

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 16/10

6:00 a.m.-12:59 p.m.

1 stop9h 59m

Seattle/Tacoma Intl

Thu 23/10

1:50 p.m.-12:45 a.m.

1 stop7h 55m

C$ 432

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 16/10

6:00 a.m.-12:59 p.m.

1 stop9h 59m

Seattle/Tacoma Intl

Wed 22/10

1:50 p.m.-12:45 a.m.

1 stop7h 55m

C$ 432

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Sat 25/10

6:00 a.m.-12:59 p.m.

1 stop9h 59m

Seattle/Tacoma Intl

Sun 2/11

11:55 a.m.-5:28 a.m.

2 stops14h 33m

C$ 478

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 17/10

6:00 a.m.-12:59 p.m.

1 stop9h 59m

Seattle/Tacoma Intl

Mon 20/10

2:05 p.m.-12:45 a.m.

1 stop7h 40m

C$ 506

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 17/10

6:00 a.m.-12:59 p.m.

1 stop9h 59m

Seattle/Tacoma Intl

Sun 19/10

8:40 a.m.-12:45 a.m.

1 stop13h 05m

C$ 509

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 6/10

6:00 a.m.-8:29 p.m.

1 stop17h 29m

Seattle/Tacoma Intl

Thu 16/10

1:50 p.m.-12:45 a.m.

1 stop7h 55m

C$ 520

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/9

Showing 1-10 of 20 results
1
2

Best time to book a flight from Region of Waterloo Intl to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Region of Waterloo Intl 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 Toronto Region of Waterloo Intl Airport to Seattle

What is the cheapest time of day to fly from YKF to SEA?

Find hourly flight availability from Region of Waterloo Intl to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 11 September 2025.

It’s typically best to fly out from Toronto Region of Waterloo Intl Airport to Seattle at noon. Doing so could potentially save you 26% on the flight price compared to flying in the morning, which is usually more expensive.

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated 11 September 2025.
Read through reviews of airlines operating flights from Toronto Region of Waterloo Intl Airport to Seattle, such as WestJet and Air Canada. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
WestJet
7.2
Good
3,091 reviews
Check prices

Boarding

7.4

Overall

7.2

Entertainment

6.1

Food

6.2

Crew

7.9

Comfort

7.1

Reviews

1 / 20
6.0
Good

Deb,Jan 2025

YYZ - YYC

Boarding went smoothly, you didn't accept debit card for food on flight
WestJet
7.2
Good
3,091 reviews
WestJet
7.2
Good
3,091 reviews
Check prices

Boarding

7.4

Overall

7.2

Entertainment

6.1

Food

6.2

Crew

7.9

Comfort

7.1

Reviews

1 / 20
6.0
Good

Deb,Jan 2025

YYZ - YYC

Boarding went smoothly, you didn't accept debit card for food on flight
Air Canada
7.1
Good
10,000 reviews
WestJet
7.2
Good
3,091 reviews
Check prices

Boarding

7.4

Overall

7.2

Entertainment

6.1

Food

6.2

Crew

7.9

Comfort

7.1

Reviews

1 / 20
6.0
Good

Deb,Jan 2025

YYZ - YYC

Boarding went smoothly, you didn't accept debit card for food on flight

Related info for your journey

Find useful and relevant information for your journey from Region of Waterloo Intl to Seattle. 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 into for flights to Seattle from Toronto Region of Waterloo Intl?

    Seattle/Tacoma Intl (SEA) is the airport you will fly into if you book a flight from Toronto Region of Waterloo Intl to Seattle. You should not have trouble finding flights to Seattle/Tacoma Intl from Toronto Region of Waterloo Intl; the airport handles an average of 0 inbound flights from Toronto Region of Waterloo Intl per day. You should also have plenty of airline options to choose from since 2 airlines have flights to the Seattle airport from Toronto Region of Waterloo Intl. It is only a 18.4 km journey from Seattle/Tacoma Intl (SEA) to Seattle’s city centre.

  • How long is the flight from Toronto Region of Waterloo Intl Airport to Seattle?

    Departing from Toronto Region of Waterloo Intl Airport to Seattle will take you 17h 29m. The distance between Toronto Region of Waterloo Intl Airport and Seattle is about 3257 km.

  • What are the cheapest airlines flying from Toronto Region of Waterloo Intl Airport to Seattle round-trip?

    WestJet, at C$ 183, was found to be the cheapest airline from Toronto Region of Waterloo Intl Airport to Seattle. An alternate airline flying to your destination would be Air Canada. WestJet is priced at 57% lower than the current average price of a flight leaving 3 months from now.

  • Can I find deals for flights from Region of Waterloo Intl to Seattle that include hotel bookings?

    Yes. In addition to deals on Region of Waterloo Intl to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Region of Waterloo Intl to Seattle?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Region of Waterloo Intl to Seattle.

  • Can I find deals for business class flights from Region of Waterloo Intl to Seattle?

    Yes. Cheapflights offers flight deals from Region of Waterloo Intl to Seattle 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 Toronto Region of Waterloo Intl Airport to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Toronto Region of Waterloo Intl Airport to Seattle (average of C$ 262). Flying from Toronto Region of Waterloo Intl Airport to Seattle in December is currently the most expensive (average of C$ 353). 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

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Leavenworth
SeaTac
Tukwila
Tacoma
Bothell
Cashmere
Renton
Olympia
Marysville
Lynnwood

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Top 2 airlines flying from Region of Waterloo Intl to Seattle

Discover the top 2 airlines that operate flights from Region of Waterloo Intl to Seattle. 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 11 September 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 183AverageC$ 308FlexibilityNo cancel feeOn-time60%
Search WestJet flights
Air CanadaCheapestC$ 378AverageC$ 393FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

Fly with Cheapflights

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How does Cheapflights help users find flights from Region of Waterloo Intl to Seattle?

Deals for Region of Waterloo Intl to Seattle flights are sourced from 900+ travel sites when you use Cheapflights. When all flight results come back, Cheapflights lets you sort and filter flights using different criteria to choose better, like price, airport, cabin class, and plenty of other options.

Why should you use Cheapflights to find cheap flight tickets from Region of Waterloo Intl to Seattle?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Region of Waterloo Intl to Seattle.

Can Cheapflights find flights from Region of Waterloo Intl to Seattle with no change fees?

Users can book flights with no change fees policies with our dedicated filters. Book flights from Region of Waterloo Intl to Seattle flexibly with Cheapflights today.

Can Cheapflights notify me if prices for flights from Region of Waterloo Intl to Seattle become cheaper?

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