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$154+ Cheap flights from Region of Waterloo Intl (YKF) to Seattle (SEA)

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 10/3. Fares are subject to change and may not be available on all flights or dates of travel.
YKF — SEA
Aug 3 — Aug 101
Sun 8/3
Sun 8/10
1 adult, Economy
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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 July 29, 2025.

Round-trip from

$249
(Trip.com)

One-way from

$154
(Trip.com)

Popular in

November

Cheapest in

May

Average price

$257
From Toronto Region of Waterloo Intl to Seattle/Tacoma Intl
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One-way flight from Toronto Region of Waterloo Intl to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 43% potential increase in price ($245 potential increase over avg. RT price).
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Cheapest flight prices on average. 22% potential price decrease ($60 potential savings vs. average RT price).
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Average for round-trip flights in July 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 July 29, 2025.

This Trip.com deal was found by Cheapflights users on 7/27. 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.
Fri 8/226:00 amYKF - SEA
1 stop9h 58mWestJet
Mon 8/252:05 pmSEA - YKF
1 stop7h 41mWestJet
Deal found 7/27$249
This Mytrip deal was found by Cheapflights users on 7/27. 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.
Wed 9/176:30 amYKF - SEA
2 stops15h 06mMultiple Airlines
Sat 9/202:55 pmSEA - YKF
2 stops11h 35mMultiple Airlines
Deal found 7/27$282

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 2,558,603 searches. Data last updated July 29, 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

Fri 8/22

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

Mon 8/25

2:05 pm-12:46 am

1 stop7h 41m

$249

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Wed 9/17

6:30 am-6:36 pm

2 stops15h 06m

Seattle/Tacoma Intl

Sat 9/20

2:55 pm-5:30 am

2 stops11h 35m

$282

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 10/3

6:15 am-12:33 pm

1 stop9h 18m

$154

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Sat 8/30

6:00 am-4:16 pm

1 stop13h 16m

$165

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/27

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 July 29, 2025.

One of the essential ways to save on airfare from Toronto Region of Waterloo Intl Airport to Seattle is to remain as flexible as possible. Flights that are at noon tend to be the most expensive. A flight in the morning could potentially save you up to 59% on airfare.

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 July 29, 2025.
Read reviews from past customers who have flown WestJet from Toronto Region of Waterloo Intl Airport to Seattle. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
WestJet
7.2
Good
2,972 reviews

Comfort

7.0

Boarding

7.4

Overall

7.2

Entertainment

6.1

Food

6.2

Crew

7.9

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
2,972 reviews
WestJet
7.2
Good
2,972 reviews

Comfort

7.0

Boarding

7.4

Overall

7.2

Entertainment

6.1

Food

6.2

Crew

7.9

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?

    For a flight from Toronto Region of Waterloo Intl to Seattle, you will be flying into Seattle/Tacoma Intl. Seattle/Tacoma Intl (SEA) is just 11.4 mi from the center of the city. Seattle/Tacoma Intl is the only Seattle airport and it handles 0 inbound flights from Toronto Region of Waterloo Intl per day. 0 airlines have flights to Seattle/Tacoma Intl from Toronto Region of Waterloo Intl on a regular basis.

  • What is the cheapest airline to fly from Toronto Region of Waterloo Intl Airport to Seattle round-trip?

    According to our current data, WestJet ($249), offers the cheapest pricing from Toronto Region of Waterloo Intl Airport to Seattle. WestJet is 23% cheaper than the average price of flights available within the next 90 days to this destination.

  • 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 $238). Flying from Toronto Region of Waterloo Intl Airport to Seattle in June is currently the most expensive (average of $389). 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

Traveling to a place near Seattle?

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