What are the cheapest airlines to fly from Region of Ontario to Seattle one-way?

$125 is the cheapest one-way deal found within the past few days, from WestJet. You may also be able to find cheap deals on Air Canada and United Airlines, with prices starting from $156 and $161, respectively.

What are the most popular routes from Region of Ontario to Seattle?

When deciding which route to take from Region of Ontario to Seattle consider Toronto Pearson Intl - Seattle/Tacoma Intl, Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl or Toronto Region of Waterloo Intl - Seattle/Tacoma Intl as they are the most popular.

What are the cheapest flights from Region of Ontario to Seattle?

On average you can expect to pay $382 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $168 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $278.

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

No one likes to see their flight delayed. When booking a flight from Region of Ontario to Seattle consider choosing Air Tahiti Nui (95%), Alaska Airlines (87%) or Hawaiian Airlines (87%) as they are the most reliable in getting you off to your destination on time.

What are the most popular airlines that fly from Region of Ontario to Seattle?

Consider Air Canada, Alaska Airlines or Delta when booking your flight. These represent the most popular airlines when flying from Region of Ontario to Seattle.

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

When searching for a good deal, it’s best to be prepared for potential fluctuations in price. We recommend booking at least 53 days in advance, which can save you up to 85% on flights from Region of Ontario to Seattle compared to booking the week you need them. Waiting 53 days out may not be for everyone, so we have options available for flights within the next two weeks, with the lowest price starting at $399. For sooner than that we have options available in the next 3 days from $753.

What is the cheapest month to fly from Region of Ontario to Seattle?

February can be a great time to fly to Seattle from Region of Ontario with a flight ticket averaging about $373. Cheapflights users have found deals in the month of February for as cheap as $212. The most expensive prices can be found in the month of July.

What airport do you fly into for flights to Seattle from Ontario?

Seattle/Tacoma Intl (SEA), located 11.4 mi from the city center, is the airport you fly into when you book flights from Ontario to Seattle.

Can I find deals for flights from Ontario to Seattle that include hotel bookings?

Yes. In addition to deals on Ontario to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Ontario to Seattle?

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

Can I find deals for business class flights from Ontario to Seattle?

Yes. Cheapflights offers flight deals from Ontario 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.

$125+ Flights from Ontario to Seattle - Compare & Save Big

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

Find cheap flights from Ontario to Seattle with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from Ontario to Seattle

Most accurate provider	FlightHub 3 stars
Most trusted provider	eDreams 3 stars
Round-trip from	$220 (FlightHub)
One-way from	$125 (Trip.com)
Popular in	July
Cheapest in	February
Average price	$433
Good round-trip deal	$365 or less
Good one-way deal	$200 or less

Provider with most accurate pricing for Toronto (YTO)-Seattle/Tacoma Intl flight deals.

Search Deals

Provider most trusted by Cheapflights users for Toronto (YTO)-Seattle/Tacoma Intl flights.

Search Deals

From Ontario to Seattle/Tacoma Intl

Search Deals

One-way flight from Ontario to Seattle/Tacoma Intl

Search Deals

Highest demand for flights based on searches. 10% potential increase in price ($43 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 1% potential price decrease ($7 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in May 2025

Search Deals

Price to beat on a round-trip flight from Ontario to Seattle/Tacoma Intl.

Search Deals

Price to beat on a one-way flight from Ontario to Seattle/Tacoma Intl.

Search Deals

Find flight deals from Ontario to Seattle

Cheapest flights from Ontario to Seattle
Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 1, 2025.

Wed 8/66:00 amYHM - SEA

1 stop9h 58mWestJet

Wed 8/131:50 pmSEA - YHM

1 stop7h 51mWestJet

Deal found 4/30

$220

Tue 5/136:00 amYKF - SEA

1 stop9h 58mWestJet

Wed 5/218:25 amSEA - YKF

1 stop13h 21mWestJet

Deal found 4/29

$234

Fri 6/63:00 pmYYZ - SEA

1 stop8h 37mAir Canada

Tue 6/102:55 pmSEA - YYZ

1 stop7h 14mAir Canada

Deal found 4/30

$256

Mon 6/236:15 amYXU - SEA

1 stop7h 36mUnited Airlines

Mon 7/1412:20 amSEA - YXU

2 stops11h 37mUnited Airlines

Deal found 4/30

$270

Tue 6/173:31 pmYYZ - SEA

1 stop9h 51mDelta

Tue 6/247:10 amSEA - YYZ

1 stop6h 34mDelta

Deal found 4/30

$274

Sun 9/218:00 amYYZ - SEA

1 stop7h 59mWestJet

Sat 9/277:05 amSEA - YYZ

1 stop8h 47mWestJet

Deal found 4/29

$281

Wed 5/214:45 pmYYZ - SEA

Nonstop5h 19mAlaska Airlines

Tue 6/37:23 amSEA - YYZ

Nonstop4h 37mAlaska Airlines

Deal found 4/29

$284

Tue 5/209:45 amYYZ - SEA

1 stop13h 57mMultiple Airlines

Tue 6/33:20 pmSEA - YYZ

2 stops26h 34mMultiple Airlines

Deal found 4/29

$285

Wed 5/2112:25 pmYTZ - SEA

1 stop10h 12mAir Canada

Tue 5/277:20 amSEA - YTZ

1 stop11h 15mAir Canada

Deal found 4/30

$289

Mon 6/239:55 amYXU - SEA

2 stops18h 09mMultiple Airlines

Tue 7/152:55 pmSEA - YXU

2 stops15h 22mMultiple Airlines

Deal found 4/30

$300

Wed 5/217:00 pmYYZ - SEA

1 stop8h 59mUnited Airlines

Tue 5/2711:23 pmSEA - YYZ

1 stop9h 36mUnited Airlines

Deal found 4/30

$309

Tue 6/171:20 pmYYZ - SEA

2 stops11h 14mAmerican Airlines

Tue 6/248:00 amSEA - YYZ

2 stops12h 28mAmerican Airlines

Deal found 4/30

$311

Best flights from Ontario to Seattle
Discover carefully curated flight deals from Ontario to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 1, 2025.

Tue 5/276:00 amYHM - SEA

1 stop9h 58mWestJet

Tue 6/32:05 pmSEA - YHM

1 stop7h 36mWestJet

Deal found 4/29

$220

Fri 6/63:00 pmYYZ - SEA

1 stop8h 37mAir Canada

Tue 6/102:55 pmSEA - YYZ

1 stop7h 14mAir Canada

Deal found 4/30

$256

Mon 6/236:15 amYXU - SEA

1 stop7h 36mUnited Airlines

Tue 7/1510:05 pmSEA - YXU

2 stops16h 02mUnited Airlines

Deal found 4/30

$270

Tue 6/173:31 pmYYZ - SEA

1 stop9h 51mDelta

Tue 6/247:10 amSEA - YYZ

1 stop6h 34mDelta

Deal found 4/30

$274

Wed 5/214:45 pmYYZ - SEA

Nonstop5h 19mAlaska Airlines

Tue 6/37:23 amSEA - YYZ

Nonstop4h 37mAlaska Airlines

Deal found 4/29

$284

Tue 5/209:45 amYYZ - SEA

1 stop13h 57mMultiple Airlines

Tue 6/33:20 pmSEA - YYZ

2 stops26h 34mMultiple Airlines

Deal found 4/29

$285

Tue 6/171:20 pmYYZ - SEA

2 stops11h 14mAmerican Airlines

Tue 6/248:00 amSEA - YYZ

2 stops12h 28mAmerican Airlines

Deal found 4/30

$311

Fri 6/68:30 amYYZ - SEA

Nonstop5h 21mLufthansa

Tue 6/1011:35 amSEA - YYZ

Nonstop4h 57mLufthansa

Deal found 4/30

$408

Tue 5/136:00 amYKF - SEA

1 stop9h 58mWestJet

Wed 5/218:25 amSEA - YKF

1 stop13h 21mWestJet

Deal found 4/29

$234

Sat 5/2412:25 pmYTZ - SEA

1 stop10h 12mAir Canada

Sat 5/317:20 amSEA - YTZ

1 stop11h 15mAir Canada

Deal found 4/30

$296

Mon 6/239:55 amYXU - SEA

2 stops18h 09mMultiple Airlines

Tue 7/152:55 pmSEA - YXU

2 stops15h 22mMultiple Airlines

Deal found 4/30

$300

Wed 5/216:20 pmYYZ - SEA

1 stop9h 39mUnited Airlines

Tue 6/31:49 pmSEA - YYZ

1 stop7h 09mUnited Airlines

Deal found 4/29

$312

Last-minute flights from Ontario to Seattle
Discover last-minute flight deals from Ontario to Seattle. Data last updated May 1, 2025 and is based on user searches.

Mon 5/54:00 pmYYZ - SEA

1 stop7h 50mDelta

Wed 5/286:00 amSEA - YYZ

1 stop6h 00mDelta

Deal found 4/30

$534

Tue 5/66:30 amYYZ - SEA

2 stops21h 26mMultiple Airlines

Tue 5/133:20 pmSEA - YYZ

3 stops30h 15mMultiple Airlines

Deal found 4/29

$377

Wed 5/76:00 amYKF - SEA

1 stop9h 58mWestJet

Wed 5/141:50 pmSEA - YKF

1 stop7h 56mWestJet

Deal found 4/29

$505

Wed 5/76:00 amYHM - SEA

1 stop9h 58mWestJet

Wed 5/141:50 pmSEA - YHM

1 stop7h 51mWestJet

Deal found 4/30

$511

Wed 5/74:05 pmYTZ - SEA

1 stop19h 25mMultiple Airlines

Wed 5/146:24 amSEA - YTZ

2 stops27h 44mMultiple Airlines

Deal found 4/30

$563

Thu 5/86:30 amYYZ - SEA

1 stop9h 17mAmerican Airlines

Tue 5/275:22 amSEA - YYZ

1 stop14h 25mAmerican Airlines

Deal found 4/28

$504

Thu 5/84:45 pmYYZ - SEA

Nonstop5h 14mAlaska Airlines

Tue 5/277:23 amSEA - YYZ

Nonstop4h 37mAlaska Airlines

Deal found 4/28

$512

Thu 5/88:25 amYYZ - SEA

Nonstop5h 20mUnited Airlines

Tue 5/271:49 pmSEA - YYZ

1 stop7h 09mUnited Airlines

Deal found 4/28

$525

Fri 5/92:00 pmYYZ - SEA

1 stop9h 50mWestJet

Wed 5/141:50 pmSEA - YYZ

1 stop7h 36mWestJet

Deal found 4/29

$487

Sat 5/108:25 amYYZ - SEA

Nonstop5h 20mAir Canada

Wed 5/217:20 amSEA - YYZ

1 stop12h 54mAir Canada

Deal found 4/30

$528

Sat 5/106:00 amYKF - SEA

2 stops13h 40mMultiple Airlines

Mon 5/123:53 pmSEA - YKF

1 stop12h 17mMultiple Airlines

Deal found 4/29

$558

Sat 5/107:00 amYUL - SEA

1 stop8h 58mMultiple Airlines

Fri 5/1612:31 pmSEA - YUL

2 stops22h 49mMultiple Airlines

Deal found 4/29

$615

One-way flights from Ontario to Seattle
Search for one-way flight options from Ontario to Seattle. Find affordable one-way fares based on user searches. Data last updated May 1, 2025.

Mon 6/96:00 amYHM - SEA

1 stop9h 58mWestJet

Deal found 4/29

$125

Sat 6/146:15 amYXU - SEA

1 stop7h 36mAir Canada

Deal found 4/30

$156

Sat 6/149:55 amYXU - SEA

2 stops13h 46mUnited Airlines

Deal found 4/30

$161

Wed 6/412:25 pmYTZ - SEA

1 stop10h 12mAir Canada

Deal found 4/29

$171

Mon 6/96:30 amYYZ - SEA

1 stop9h 28mWestJet

Deal found 4/29

$174

Thu 6/54:45 pmYYZ - SEA

Nonstop5h 19mAlaska Airlines

Deal found 4/29

$175

Mon 9/296:00 amYKF - SEA

1 stop9h 59mWestJet

Deal found 4/29

$176

Thu 6/55:50 pmYYZ - SEA

1 stop7h 35mDelta

Deal found 4/29

$176

Wed 6/47:00 amYYZ - SEA

1 stop8h 58mAir Canada

Deal found 4/29

$178

Tue 5/276:00 amYKF - SEA

2 stops35h 25mMultiple Airlines

Deal found 4/29

$181

Mon 6/238:05 pmYYZ - SEA

1 stop21h 58mMultiple Airlines

Deal found 4/29

$182

Tue 6/242:45 pmYYZ - SEA

2 stops13h 14mUnited Airlines

Deal found 4/30

$184

Cheapflights Fare Finder

Use the filters below to find and compare flights from Ontario to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

HamiltonSeattle

YHM - SEA

YHMSEA

Hamilton

Wed 8/6

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

Wed 8/13

1:50 pm-12:41 am

1 stop7h 51m

$220

TorontoSeattle

YKF - SEA

YKFSEA

Toronto Region of Waterloo Intl

Tue 5/13

6:00 am-12:58 pm

1 stop9h 58m

Seattle/Tacoma Intl

Wed 5/21

8:25 am-12:46 am

1 stop13h 21m

$234

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Fri 6/6

3:00 pm-8:37 pm

1 stop8h 37m

Seattle/Tacoma Intl

Tue 6/10

2:55 pm-1:09 am

1 stop7h 14m

$256

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 6/23

6:15 am-10:51 am

1 stop7h 36m

Seattle/Tacoma Intl

Tue 7/15

10:05 pm-5:07 pm

2 stops16h 02m

$270

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 6/17

5:50 pm-12:04 am

1 stop9h 14m

Seattle/Tacoma Intl

Wed 6/25

11:50 pm-9:21 am

1 stop6h 31m

$274

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Sun 9/21

8:00 am-12:59 pm

1 stop7h 59m

Seattle/Tacoma Intl

Sat 9/27

7:05 am-6:52 pm

1 stop8h 47m

$281

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Wed 5/21

4:45 pm-7:04 pm

Nonstop5h 19m

Seattle/Tacoma Intl

Tue 6/3

7:23 am-3:00 pm

Nonstop4h 37m

$284

TorontoSeattle

YYZ - SEA

YYZSEA

Toronto Pearson Intl

Tue 5/20

9:45 am-8:42 pm

1 stop13h 57m

Seattle/Tacoma Intl

Tue 6/3

3:20 pm-8:54 pm

2 stops26h 34m

$285

TorontoSeattle

YTZ - SEA

YTZSEA

Toronto Island

Wed 5/21

12:25 pm-7:37 pm

1 stop10h 12m

Seattle/Tacoma Intl

Tue 5/27

7:20 am-9:35 pm

1 stop11h 15m

$289

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 6/23

9:55 am-1:04 am

2 stops18h 09m

Seattle/Tacoma Intl

Tue 7/15

2:55 pm-9:17 am

2 stops15h 22m

$300

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/29

Showing 1-10 of 55 results

...

Best time to book a flight from Ontario to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Ontario 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 Ontario to Seattle

What is the cheapest month to book a flight from Region of Ontario to Seattle?

Currently, January is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $238). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of $405). 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 ON to SEA?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Region of Ontario to Seattle as you normally would.

Weekly flight availability from Region of Ontario to Seattle

The most flights from CAON to SEA are scheduled on a Wednesday (6 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (1 on average).

Rainfall in Seattle by month

In terms of precipitation, rainfall in Seattle ranges from 0.7 - 6.6 inches per month. November is typically the wettest month, when rainfall can reach 6.6 in. July is typically the driest time to visit Seattle when rainfall is around 0.7 in.

Temperature in Seattle by month

If weather is an important factor for your trip to Seattle, 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 66.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 41.0 F).

Reviews of airlines servicing Seattle

Read reviews from past customers who have flown Alaska Airlines, Delta and United Airlines from Ontario to Seattle. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Alaska Airlines

8.0

Very good

9,968 reviews

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Alaska Airlines

8.0

Very good

9,968 reviews

Alaska Airlines

8.0

Very good

9,968 reviews

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Delta

8.0

Very good

7,934 reviews

Alaska Airlines

8.0

Very good

9,968 reviews

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

United Airlines

7.4

Good

8,696 reviews

Alaska Airlines

8.0

Very good

9,968 reviews

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

American Airlines

7.2

Good

10,000 reviews

Alaska Airlines

8.0

Very good

9,968 reviews

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

WestJet

7.2

Good

2,826 reviews

Alaska Airlines

8.0

Very good

9,968 reviews

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Related info for your journey

What airport do you fly into for flights to Seattle from Ontario?
Seattle/Tacoma Intl (SEA), located 11.4 mi from the city center, is the airport you fly into when you book flights from Ontario to Seattle.
What are the cheapest airlines to fly from Region of Ontario to Seattle one-way?
$125 is the cheapest one-way deal found within the past few days, from WestJet. You may also be able to find cheap deals on Air Canada and United Airlines, with prices starting from $156 and $161, respectively.
What are the most popular routes from Region of Ontario to Seattle?
When deciding which route to take from Region of Ontario to Seattle consider Toronto Pearson Intl - Seattle/Tacoma Intl, Montreal Pierre Elliott Trudeau Intl - Seattle/Tacoma Intl or Toronto Region of Waterloo Intl - Seattle/Tacoma Intl as they are the most popular.
What are the most reliable airlines from Region of Ontario to Seattle?
No one likes to see their flight delayed. When booking a flight from Region of Ontario to Seattle consider choosing Air Tahiti Nui (95%), Alaska Airlines (87%) or Hawaiian Airlines (87%) as they are the most reliable in getting you off to your destination on time.
What are the cheapest flights from Region of Ontario to Seattle?
On average you can expect to pay $382 for a flight from Region of Ontario to Seattle. The cheapest flight overall is $168 while the most popular route, (Toronto Pearson Intl - Seattle/Tacoma Intl) is currently priced at $278.
Can I find deals for flights from Ontario to Seattle that include hotel bookings?
Yes. In addition to deals on Ontario to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Ontario to Seattle?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Seattle.
Can I find deals for business class flights from Ontario to Seattle?
Yes. Cheapflights offers flight deals from Ontario 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 Region of Ontario to Seattle?
Currently, January is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $238). Flying from Region of Ontario to Seattle in July is currently the most expensive (average of $405). 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

SeaTac

Tukwila

Tacoma

Lakewood

Renton

Ocean Shores

Lacey

Leavenworth

Federal Way

Olympia

Shoreline

Cle Elum

Centralia

Kent

Lynnwood

Aberdeen

Shelton

Silverdale

Redmond

Issaquah

Browse thousands of different options on Cheapflights for your next trip

Top 5 airlines flying from Ontario to Seattle

Airline	Cheapest	Average	Flexibility	On-time
WestJet	Cheapest$141	Average$342	FlexibilityNo cancel fee	On-time60%
Alaska Airlines	Cheapest$239	Average$414	FlexibilityNo cancel fee	On-time75%
United Airlines	Cheapest$240	Average$442	FlexibilityNo cancel fee	On-time69%
Air Canada	Cheapest$250	Average$440	FlexibilityNo cancel fee	On-time67%
Delta	Cheapest$292	Average$401	FlexibilityNo cancel fee	On-timeN/A

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.

$125+ Cheap flights from Ontario 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 6/9. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Ontario to Seattle with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Ontario to Seattle

Keep the following information in mind while searching for Ontario to Seattle flight deals. Data was last updated May 1, 2025.

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good round-trip deal

Good one-way deal

Find flight deals from Ontario to Seattle

Cheapest flights from Ontario to SeattleExplore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 1, 2025.

Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 1, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Ontario to Seattle that are best for you.

Best time to book a flight from Ontario to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Ontario with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Ontario to Seattle

What is the cheapest month to book a flight from Region of Ontario to Seattle?

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

Find hourly flight availability from Ontario 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 May 1, 2025.

Weekly flight availability from Region of Ontario to Seattle

Explore weekly flight availability from Ontario to Seattle. 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 May 1, 2025.

Rainfall in Seattle by month

Plan your trip to Seattle by taking into account the average rainfall totals by month.

Temperature in Seattle by month

Plan your trip to Seattle by taking into account the average temperature totals by month.

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 May 1, 2025.

Read reviews from past customers who have flown Alaska Airlines, Delta and United Airlines from Ontario to Seattle. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Ontario 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 Ontario?

What are the cheapest airlines to fly from Region of Ontario to Seattle one-way?

What are the most popular routes from Region of Ontario to Seattle?

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

What are the cheapest flights from Region of Ontario to Seattle?

Can I find deals for flights from Ontario to Seattle that include hotel bookings?

How can I find direct flights from Ontario to Seattle?

Can I find deals for business class flights from Ontario to Seattle?

What is the cheapest month to book a flight from Region of Ontario to Seattle?

Traveling to a place near Ontario?

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 Ontario to Seattle

See prices for flight routes from nearby airports that may be better suited for you.

Top 5 airlines flying from Ontario to Seattle

100% Free

Book with Flexibility

Travel Smart

Cheapest flights from Ontario to Seattle
Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 1, 2025.