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Cheap flights from Toronto Region of Waterloo Intl Airport to Seattle from $144

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Toronto Region of Waterloo Intl Airport to Seattle departing on 5/25. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Find the cheapest flights from Toronto Region of Waterloo Intl Airport to Seattle

Cheap round-trip flights

Enter your travel dates to find the best prices.
WestJet Logo
6:20 am - 2:19 pm
YKF
-
SEA
10h 59m
1 stop
WestJet Logo
3:10 pm - 5:29 am
SEA
-
YKF
11h 19m
1 stop
$260WestJet
Mon, Apr 6 - Wed, Apr 15
WestJet Logo
6:20 am - 2:19 pm
YKF
-
SEA
10h 59m
1 stop
WestJet Logo
7:35 pm - 7:50 pm
SEA
-
YKF
21h 15m
1 stop
$265WestJet
Thu, Apr 23 - Tue, May 12
WestJet Logo
8:40 pm - 6:45 pm
YKF
-
SEA
25h 05m
1 stop
WestJet Logo
7:35 pm - 7:50 pm
SEA
-
YKF
21h 15m
1 stop
$272WestJet
Fri, May 29 - Mon, Jun 8
WestJet Logo
8:40 pm - 9:40 am
YKF
-
SEA
16h 00m
1 stop
WestJet Logo
7:35 pm - 7:50 pm
SEA
-
YKF
21h 15m
1 stop
$288WestJet
Sun, May 24 - Thu, May 28
WestJet Logo
8:40 pm - 6:45 pm
YKF
-
SEA
25h 05m
1 stop
WestJet Logo
2:05 pm - 12:45 am
SEA
-
YKF
7h 40m
1 stop
$367WestJet
Mon, Jun 15 - Mon, Jun 22
WestJet Logo
6:20 am - 2:19 pm
YKF
-
SEA
10h 59m
1 stop
WestJet Logo
3:10 pm - 5:29 am
SEA
-
YKF
11h 19m
1 stop
$374WestJet
Tue, Mar 24 - Wed, Mar 25
Multiple Airlines Logo
7:05 am - 2:19 pm
YKF
-
SEA
10h 14m
1 stop
Multiple Airlines Logo
3:10 pm - 5:29 am
SEA
-
YKF
11h 19m
1 stop
$384Multiple Airlines
Sun, Apr 12 - Fri, Apr 17
WestJet Logo
6:20 am - 2:19 pm
YKF
-
SEA
10h 59m
1 stop
WestJet Logo
3:10 pm - 5:29 am
SEA
-
YKF
11h 19m
1 stop
$413WestJet
Tue, Mar 24 - Wed, Apr 1
WestJet Logo
6:20 am - 2:19 pm
YKF
-
SEA
10h 59m
1 stop
WestJet Logo
3:10 pm - 5:29 am
SEA
-
YKF
11h 19m
1 stop
$420WestJet
Mon, Mar 2 - Mon, Mar 9
Multiple Airlines Logo
7:05 am - 2:19 pm
YKF
-
SEA
10h 14m
1 stop
Multiple Airlines Logo
11:55 am - 5:29 am
SEA
-
YKF
14h 34m
2 stops
$427Multiple Airlines
Sun, Apr 12 - Fri, Apr 17

WestJet flights from Toronto Region of Waterloo Intl Airport to Seattle

Our best WestJet deals on Toronto Region of Waterloo Intl Airport to Seattle flight tickets
WestJet
Apr 6
YKF6:20 amToronto Region of Waterloo Intl
10h 59m
1 stop
SEA2:19 pmSeattle/Tacoma Intl
Apr 15
SEA3:10 pmSeattle/Tacoma Intl
11h 19m
1 stop
YKF5:29 amToronto Region of Waterloo Intl
$260
WestJet
Apr 23
YKF6:20 amToronto Region of Waterloo Intl
10h 59m
1 stop
SEA2:19 pmSeattle/Tacoma Intl
May 12
SEA7:35 pmSeattle/Tacoma Intl
21h 15m
1 stop
YKF7:50 pmToronto Region of Waterloo Intl
$265
WestJet
May 29
YKF8:40 pmToronto Region of Waterloo Intl
25h 05m
1 stop
SEA6:45 pmSeattle/Tacoma Intl
Jun 8
SEA7:35 pmSeattle/Tacoma Intl
21h 15m
1 stop
YKF7:50 pmToronto Region of Waterloo Intl
$272

momondo Fare Finder

 
Customize your flight search to find flights from Toronto Region of Waterloo Intl Airport 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, momondo users made 832,500 searches. Data last updated February 5, 2026.
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

Fly to

Route

Depart

Return

Price

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 4/6

6:20 am-2:19 pm

1 stop10h 59m

Seattle/Tacoma Intl

Wed 4/15

3:10 pm-5:29 am

1 stop11h 19m

$260

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Thu 4/23

6:20 am-2:19 pm

1 stop10h 59m

Seattle/Tacoma Intl

Tue 5/12

7:35 pm-7:50 pm

1 stop21h 15m

$265

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Fri 5/29

8:40 pm-6:45 pm

1 stop25h 05m

Seattle/Tacoma Intl

Mon 6/8

7:35 pm-7:50 pm

1 stop21h 15m

$272

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Sun 5/24

8:40 pm-9:40 am

1 stop16h 00m

Seattle/Tacoma Intl

Thu 5/28

7:35 pm-7:50 pm

1 stop21h 15m

$288

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 6/15

8:40 pm-6:45 pm

1 stop25h 05m

Seattle/Tacoma Intl

Mon 6/22

2:05 pm-12:45 am

1 stop7h 40m

$367

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Tue 3/24

6:20 am-2:19 pm

1 stop10h 59m

Seattle/Tacoma Intl

Wed 3/25

3:10 pm-5:29 am

1 stop11h 19m

$374

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Sun 4/12

7:05 am-2:19 pm

1 stop10h 14m

Seattle/Tacoma Intl

Fri 4/17

3:10 pm-5:29 am

1 stop11h 19m

$384

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Tue 3/24

6:20 am-2:19 pm

1 stop10h 59m

Seattle/Tacoma Intl

Wed 4/1

3:10 pm-5:29 am

1 stop11h 19m

$413

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Mon 3/2

6:20 am-2:19 pm

1 stop10h 59m

Seattle/Tacoma Intl

Mon 3/9

3:10 pm-5:29 am

1 stop11h 19m

$420

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Sun 4/12

7:05 am-2:19 pm

1 stop10h 14m

Seattle/Tacoma Intl

Fri 4/17

11:55 am-5:29 am

2 stops14h 34m

$427

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Seattle from

How to get the cheapest flight ticket from Toronto Region of Waterloo Intl Airport to Seattle

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest day to depart on your flight to Seattle?

On average, the least expensive day to fly to Seattle from Toronto Region of Waterloo Intl Airport is on a Thursday. momondo users have found tickets for Thursday departures for as low as $395. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from Toronto Region of Waterloo Intl Airport because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $854.

What is the cheapest time of day to depart on your flight to Seattle?

Flying to Seattle from Toronto Region of Waterloo Intl Airport in the evening is the least expensive time of day to depart. momondo users have found prices as low as $309 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $538. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

When to book flights from Toronto Region of Waterloo Intl Airport to Seattle

Are you open to changing your travel dates? Check out the ideal times to fly from Toronto Region of Waterloo Intl Airport to Seattle according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Toronto Region of Waterloo Intl Airport to Seattle (YKF to SEA) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Toronto Region of Waterloo Intl Airport to Seattle

Fastest flight time

10h 59m

Direct flights

None
The fastest flight from Toronto Region of Waterloo Intl Airport to Seattle takes 10h 59m
There are no direct flights from Toronto Region of Waterloo Intl Airport to Seattle. There are no popular flight routes from Toronto Region of Waterloo Intl Airport to Seattle.
Search flight deals

  • How far is Toronto Region of Waterloo Intl to Seattle/Tacoma Intl by plane?

    Seattle/Tacoma Intl is 2024.0 mi away from Toronto Region of Waterloo Intl. A reasonable flight in good conditions will take 10h 59m.

  • When did momondo last update prices for flights from Toronto Region of Waterloo Intl Airport to Seattle/Tacoma Intl Airport?

    Prices for flights from Toronto Region of Waterloo Intl Airport to Seattle/Tacoma Intl Airport are refreshed on a daily basis.

  • How old do you have to be to fly from Toronto Region of Waterloo Intl Airport to Seattle/Tacoma Intl Airport?

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Toronto Region of Waterloo Intl Airport to Seattle/Tacoma Intl Airport.

  • What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?

    The travel and health documents you'll need for your trip to Seattle/Tacoma Intl Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Seattle/Tacoma Intl Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Tacoma
Leavenworth
SeaTac
Ocean Shores
Renton
Olympia
Lynnwood
Kent
Marysville
Redmond
Puyallup
Cle Elum
Tukwila
Lakewood
Federal Way
Westport
Kirkland
Centralia
Fife
Tumwater

Why use momondo?

Why should I use momondo to find a flight deal from Toronto to Seattle?

It is quick and easy to find Toronto to Seattle flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to Seattle that suits you.

Can I find flights from Toronto to Seattle with flexible booking policies on momondo?

Yes. momondo allows you to filter the results for Toronto to Seattle flights to just show those with flexible booking policies.

How can momondo help me find flights from Toronto to Seattle?

Once you have performed a search for Toronto to Seattle flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

I’m not ready to book a flight from Toronto to Seattle right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to Seattle from Toronto. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

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