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Cheap flights from Seattle to Ontario from C$ 111

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 17/6. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ONT
16 Apr — 23 Apr1
1 adult

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Ontario are usually found in September or August, booked 72 days in advance, depart on a Saturday or Tuesday and return on a Saturday

Cheap flight deals from Seattle to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Ontario (ONT). 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 April 2025.

Round-trip from

C$ 212

One-way from

C$ 111

Popular in

December

Cheapest in

September

Average price

C$ 320

Good round-trip deal

C$ 173 or less

Good one-way deal

C$ 88 or less
Alaska Airlines
  • Alaska Airlines
  • 3/6-3/6
  • Nonstop
  • 5h 12m total
  • Seattle to Ontario
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Hawaiian Airlines
  • Hawaiian Airlines
  • 17/6
  • Nonstop
  • 2h 43m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 12% potential increase in price (C$ 51 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease (C$ 14 potential savings vs. average RT price).
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Average for round-trip flights in April 2025
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to Ontario.
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Price to beat on a one-way flight from Seattle/Tacoma Intl to Ontario.
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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 11 April 2025.

Tue 3/61:18 p.m.SEA - ONT
Nonstop2h 32mAlaska Airlines
Tue 3/67:20 p.m.ONT - SEA
Nonstop2h 40mAlaska Airlines
Deal found 10/4C$ 212
Tue 13/57:55 p.m.SEA - ONT
Nonstop2h 40mDelta
Sat 17/57:05 p.m.ONT - SEA
Nonstop3h 02mDelta
Deal found 10/4C$ 220
Thu 8/55:05 a.m.SEA - ONT
1 stop7h 19mUnited Airlines
Sun 11/56:00 a.m.ONT - SEA
1 stop5h 49mUnited Airlines
Deal found 10/4C$ 241
Sun 20/412:46 p.m.SEA - ONT
Nonstop2h 39mFrontier
Tue 22/412:10 p.m.ONT - SEA
1 stop12h 34mFrontier
Deal found 10/4C$ 258
Tue 20/59:15 a.m.SEA - ONT
1 stop6h 20mSouthwest
Sun 25/51:55 p.m.ONT - SEA
1 stop7h 45mSouthwest
Deal found 10/4C$ 270
Tue 29/45:55 p.m.SEA - ONT
Nonstop2h 34mHawaiian Airlines
Sat 10/54:29 p.m.ONT - SEA
Nonstop2h 41mHawaiian Airlines
Deal found 9/4C$ 277
Sun 20/412:46 p.m.SEA - ONT
Nonstop2h 39mMultiple Airlines
Tue 22/411:46 a.m.ONT - SEA
Nonstop2h 45mMultiple Airlines
Deal found 10/4C$ 286

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 11 April 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

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 3/6

1:18 p.m.-3:50 p.m.

Nonstop2h 32m

Ontario

Tue 3/6

7:20 p.m.-10:00 p.m.

Nonstop2h 40m

C$ 212

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 13/5

7:55 p.m.-10:35 p.m.

Nonstop2h 40m

Ontario

Sat 17/5

7:05 p.m.-10:07 p.m.

Nonstop3h 02m

C$ 220

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 8/5

5:05 a.m.-12:24 p.m.

1 stop7h 19m

Ontario

Sun 11/5

6:00 a.m.-11:49 a.m.

1 stop5h 49m

C$ 241

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sun 20/4

12:46 p.m.-3:25 p.m.

Nonstop2h 39m

Ontario

Tue 22/4

12:10 p.m.-12:44 a.m.

1 stop12h 34m

C$ 258

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 20/5

9:15 a.m.-3:35 p.m.

1 stop6h 20m

Ontario

Sun 25/5

1:55 p.m.-9:40 p.m.

1 stop7h 45m

C$ 270

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 29/4

5:55 p.m.-8:29 p.m.

Nonstop2h 34m

Ontario

Sat 10/5

4:29 p.m.-7:10 p.m.

Nonstop2h 41m

C$ 277

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sun 20/4

12:46 p.m.-3:25 p.m.

Nonstop2h 39m

Ontario

Tue 22/4

11:46 a.m.-2:31 p.m.

Nonstop2h 45m

C$ 286

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 17/6

9:30 p.m.-12:13 a.m.

Nonstop2h 43m

C$ 111

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 8/5

5:05 a.m.-12:24 p.m.

1 stop7h 19m

C$ 118

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 9/5

8:13 a.m.-10:51 a.m.

Nonstop2h 38m

C$ 125

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/4

Showing 1-10 of 12 results
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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

How far ahead should I book a flight from Seattle to Ontario?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Ontario. Price data was last updated on 4 April 2025.

Booking 72 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to Ontario. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, September is the cheapest month in which you can book a flight from Seattle to Ontario (average of C$ 290). Flying from Seattle to Ontario in May is currently the most expensive (average of C$ 574). 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 ONT?

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 11 April 2025.

One of the essential ways to save on airfare from Seattle to Ontario is to remain as flexible as possible. Flights that are in the evening tend to be the most expensive. A flight at noon could potentially save you up to 47% on airfare.

What is the cheapest day to fly from Seattle to Ontario?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Ontario. Price data was last updated on 30 March 2025.

Travelers seeking maximum savings on their Seattle to Ontario flight should consider departing on Saturday at noon when fares are most often at their lowest. Monday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Seattle to Ontario

Explore weekly flight availability from Seattle to Ontario. 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 11 April 2025.

The most flights from SEA to ONT are scheduled on a Thursday (18 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (2 on average).

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 Ontario ranges from 3.0 - 86.0 mm per month. February is typically the wettest month, when rainfall can reach 86.0 mm. June is typically the driest time to visit Ontario when rainfall is around 3.0 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 Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 26.0 C. Travellers hoping to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 12.0 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 11 April 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest and Delta from Seattle to Ontario. 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.
Alaska Airlines
8.0
Very good
9,851 reviews
Check prices

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.1

Food

7.1

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
9,851 reviews
Alaska Airlines
8.0
Very good
9,851 reviews
Check prices

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.1

Food

7.1

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 😥
Southwest
8.0
Very good
4,279 reviews
Alaska Airlines
8.0
Very good
9,851 reviews
Check prices

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.1

Food

7.1

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
7,910 reviews
Alaska Airlines
8.0
Very good
9,851 reviews
Check prices

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.1

Food

7.1

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
2,366 reviews
Alaska Airlines
8.0
Very good
9,851 reviews
Check prices

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.1

Food

7.1

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
8,636 reviews
Alaska Airlines
8.0
Very good
9,851 reviews
Check prices

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.1

Food

7.1

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 airports do I use to fly from Seattle to Ontario?

    To fly from Seattle to Ontario, you need to book a flight from Seattle/Tacoma Intl (SEA) to Ontario (ONT). Nonstop flights to Ontario from Seattle/Tacoma Intl take 2h 31m on average. When it comes time to book airfare, you have a few options: there are 12 outbound flights from Seattle/Tacoma Intl to Ontario offered by 2 different airlines.

  • How popular is this Seattle to Ontario flight route?

    Within the past month, 48 users have taken a look at flights from Seattle/Tacoma Intl to Ontario.

  • What are the cheapest airlines flying from Seattle to Ontario round-trip?

    Cheapflights users have booked flights from Seattle to Ontario round-trip from C$ 212. Other airlines that can offer you cheap pricing are Delta, from C$ 220, and United Airlines, from C$ 241. Alaska Airlines is currently priced 21% below the average price you’ll pay for this route.

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

    C$ 111 is the cheapest one-way deal found within the past few days, from Hawaiian Airlines. You may also be able to find cheap deals on United Airlines and Alaska Airlines, with prices starting from C$ 118 and C$ 125, respectively.

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

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Seattle to Ontario on time: KLM (95%), WestJet (94%), Korean Air (90%).

  • What are the cheapest flights from Seattle to Ontario?

    Looking for the cheapest flight from Seattle to Ontario? While on average our users pay C$ 242, our data indicates the cheapest price to be C$ 77. The most popular route (Seattle/Tacoma Intl - Ontario), is priced around C$ 201.

  • 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 Ontario?

    Currently, September is the cheapest month in which you can book a flight from Seattle to Ontario (average of C$ 290). Flying from Seattle to Ontario in May is currently the most expensive (average of C$ 574). 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

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Top 2 airlines flying from Seattle to Ontario

Discover the top 2 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 11 April 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapestC$ 81AverageC$ 150FlexibilityNo cancel feeOn-time62%
Search Frontier flights
Alaska AirlinesCheapestC$ 152AverageC$ 309FlexibilityNo 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?

When you search for this flight from Seattle to Ontario, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Seattle to Ontario?

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 Seattle to Ontario.

Can Cheapflights find flights from Seattle to Ontario with no change fees?

Yes! Cheapflights helps users easily find flights from Seattle to Ontario with no change fees.

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!

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