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Cheap flights from Seattle to Ontario from C$ 96

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 20/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ONT
4 May — 11 May1
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 29 April 2025.

Round-trip from

C$ 148

One-way from

C$ 96

Popular in

December

Cheapest in

September

Average price

C$ 327
Frontier
  • Frontier
  • 19/5-25/5
  • Nonstop
  • 5h 35m total
  • Seattle to Ontario
Search Deals
Hawaiian Airlines
  • Hawaiian Airlines
  • 20/5
  • Nonstop
  • 2h 31m total
  • Seattle to Ontario
Search Deals
Highest demand for flights based on searches. 11% potential increase in price (C$ 49 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (C$ 15 potential savings vs. average RT price).
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Average for round-trip flights in April 2025
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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 29 April 2025.

Mon 19/56:50 p.m.SEA - ONT
Nonstop2h 35mFrontier
Sun 25/510:03 a.m.ONT - SEA
Nonstop3h 00mFrontier
Deal found 28/4C$ 148
Tue 3/61:18 p.m.SEA - ONT
Nonstop2h 32mAlaska Airlines
Tue 3/67:20 p.m.ONT - SEA
Nonstop2h 40mAlaska Airlines
Deal found 29/4C$ 182
Tue 20/511:30 a.m.SEA - ONT
Nonstop2h 45mDelta
Wed 21/52:55 p.m.ONT - SEA
Nonstop3h 00mDelta
Deal found 28/4C$ 218
Thu 22/55:10 a.m.SEA - ONT
1 stop7h 04mUnited Airlines
Tue 27/51:36 p.m.ONT - SEA
1 stop7h 35mUnited Airlines
Deal found 28/4C$ 276
Sat 24/56:30 a.m.SEA - ONT
1 stop5h 30mSouthwest
Sun 25/51:55 p.m.ONT - SEA
1 stop7h 45mSouthwest
Deal found 28/4C$ 280
Sat 31/58:26 a.m.SEA - ONT
Nonstop2h 31mMultiple Airlines
Sun 1/61:36 p.m.ONT - SEA
1 stop4h 49mMultiple Airlines
Deal found 28/4C$ 600

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 29 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

Mon 19/5

6:50 p.m.-9:25 p.m.

Nonstop2h 35m

Ontario

Sun 25/5

10:03 a.m.-1:03 p.m.

Nonstop3h 00m

C$ 148

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$ 182

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 20/5

11:30 a.m.-2:15 p.m.

Nonstop2h 45m

Ontario

Wed 21/5

2:55 p.m.-5:55 p.m.

Nonstop3h 00m

C$ 218

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 22/5

5:10 a.m.-12:14 p.m.

1 stop7h 04m

Ontario

Tue 27/5

1:36 p.m.-9:11 p.m.

1 stop7h 35m

C$ 276

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 24/5

6:30 a.m.-12:00 p.m.

1 stop5h 30m

Ontario

Sun 25/5

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

1 stop7h 45m

C$ 280

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 31/5

8:26 a.m.-10:57 a.m.

Nonstop2h 31m

Ontario

Sun 1/6

1:36 p.m.-6:25 p.m.

1 stop4h 49m

C$ 600

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 20/5

8:26 a.m.-10:57 a.m.

Nonstop2h 31m

C$ 96

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Wed 21/5

3:35 p.m.-6:20 p.m.

Nonstop2h 45m

C$ 109

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 20/5

7:00 a.m.-12:24 p.m.

1 stop5h 24m

C$ 123

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sun 1/6

5:30 a.m.-11:35 a.m.

1 stop6h 05m

C$ 137

Flights are sorted by cheapest round-trip flights first.

Deals found on 28/4

Showing 1-10 of 13 results
1
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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 25 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 29 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 29 April 2025.

The most flights from SEA to ONT are scheduled on a Monday (22 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (12 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 29 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
9,961 reviews
Check prices

Comfort

7.9

Entertainment

7.1

Crew

8.5

Overall

8.0

Boarding

8.2

Food

7.1

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
9,961 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Comfort

7.9

Entertainment

7.1

Crew

8.5

Overall

8.0

Boarding

8.2

Food

7.1

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
4,292 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Comfort

7.9

Entertainment

7.1

Crew

8.5

Overall

8.0

Boarding

8.2

Food

7.1

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
7,929 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Comfort

7.9

Entertainment

7.1

Crew

8.5

Overall

8.0

Boarding

8.2

Food

7.1

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
2,401 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Comfort

7.9

Entertainment

7.1

Crew

8.5

Overall

8.0

Boarding

8.2

Food

7.1

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
8,696 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Comfort

7.9

Entertainment

7.1

Crew

8.5

Overall

8.0

Boarding

8.2

Food

7.1

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 36m on average. When it comes time to book airfare, you have a few options: there are 18 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, 47 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$ 148. Other airlines that can offer you cheap pricing are Alaska Airlines, from C$ 182, and Delta, from C$ 218. Frontier is currently priced 44% below the average price you’ll pay for this route.

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

    C$ 96 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 Delta and United Airlines, with prices starting from C$ 109 and C$ 123, 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: WestJet (98%), Korean Air (97%), KLM (95%).

  • 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 29 April 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapestC$ 81AverageC$ 158FlexibilityNo cancel feeOn-time62%
Search Frontier flights
Alaska AirlinesCheapestC$ 150AverageC$ 305FlexibilityNo 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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