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$59+ Cheap flights from Ontario to Seattle (ONT - 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 2/20. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SEA
feb. 18 — feb. 251
mar. 2/18
mar. 2/25
1 adult, Economy
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The best prices from Ontario to Seattle/Tacoma Intl are usually found in October or January, booked 78 days in advance, depart on a Friday or Saturday and return on a Thursday

Cheap flight deals from Ontario to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) 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 febrero 13, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$92
(Cheapflightsfares)

One-way from

$59
(Cheapflightsfares)

Popular in

December

Cheapest in

October

Average price

$196

Good round-trip deal

$161 or less

Good one-way deal

$121 or less
Provider with most accurate pricing for Ontario-Seattle/Tacoma Intl flight deals.
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Provider most trusted by Cheapflights users for Ontario-Seattle/Tacoma Intl flights.
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From Ontario to Seattle/Tacoma Intl
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One-way flight from Ontario to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 2% potential increase in price ($4 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($6 potential savings vs. average RT price).
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Average for round-trip flights in February 2025
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Price to beat on a round-trip flight from Ontario to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from Ontario to Seattle/Tacoma Intl.
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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 febrero 13, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 2/11. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 3/311:25 amONT - SEA
Nonstop2h 51mFrontier
vie. 3/712:52 pmSEA - ONT
Nonstop2h 37mFrontier
Deal found 2/11$92
This Expedia deal was found by Cheapflights users on 2/13. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 5/124:29 pmONT - SEA
Nonstop3h 03mMultiple Airlines
mar. 5/208:15 pmSEA - ONT
Nonstop2h 31mMultiple Airlines
Deal found 2/13$133
This Alaska Airlines deal was found by Cheapflights users on 2/13. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 3/186:00 amONT - SEA
Nonstop2h 50mAlaska Airlines
mar. 3/186:55 pmSEA - ONT
Nonstop2h 32mAlaska Airlines
Deal found 2/13$177
This Delta deal was found by Cheapflights users on 2/13. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 5/102:00 pmONT - SEA
Nonstop2h 57mDelta
jue. 5/227:59 amSEA - ONT
Nonstop2h 48mDelta
Deal found 2/13$197
This Kissandfly.com deal was found by Cheapflights users on 2/13. 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 Kissandfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 4/166:00 amONT - SEA
Nonstop2h 50mHawaiian Airlines
mié. 4/233:24 pmSEA - ONT
1 stop4h 57mHawaiian Airlines
Deal found 2/13$205
This Southwest deal was found by Cheapflights users on 2/11. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 3/135:40 amONT - SEA
1 stop5h 05mSouthwest
dom. 3/168:15 pmSEA - ONT
1 stop11h 25mSouthwest
Deal found 2/11$212
This United Airlines deal was found by Cheapflights users on 2/13. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 3/136:00 amONT - SEA
1 stop7h 43mUnited Airlines
sáb. 3/155:40 pmSEA - ONT
1 stop5h 05mUnited Airlines
Deal found 2/13$227

Find flights from Ontario to Seattle within your budget

Customize your flight search to find flights from Ontario 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 febrero 13, 2025.

Fly from

Ontario

Fly to

Seattle

Route

Depart

Return

Price

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

lun. 3/3

11:25 am-2:16 pm

Nonstop2h 51m

Seattle/Tacoma Intl

vie. 3/7

12:52 pm-3:29 pm

Nonstop2h 37m

$92

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

lun. 5/12

4:29 pm-7:32 pm

Nonstop3h 03m

Seattle/Tacoma Intl

mar. 5/20

8:15 pm-10:46 pm

Nonstop2h 31m

$133

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

mar. 3/18

6:00 am-8:50 am

Nonstop2h 50m

Seattle/Tacoma Intl

mar. 3/18

6:55 pm-9:27 pm

Nonstop2h 32m

$177

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

sáb. 5/10

2:00 pm-4:57 pm

Nonstop2h 57m

Seattle/Tacoma Intl

sáb. 5/17

2:35 pm-5:14 pm

Nonstop2h 39m

$197

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

mié. 4/16

6:00 am-8:50 am

Nonstop2h 50m

Seattle/Tacoma Intl

mié. 4/23

3:24 pm-8:21 pm

1 stop4h 57m

$205

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

jue. 3/13

5:40 am-10:45 am

1 stop5h 05m

Seattle/Tacoma Intl

dom. 3/16

8:15 pm-7:40 am

1 stop11h 25m

$212

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

jue. 3/13

6:00 am-1:43 pm

1 stop7h 43m

Seattle/Tacoma Intl

sáb. 3/15

5:40 pm-10:45 pm

1 stop5h 05m

$227

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

jue. 2/20

10:21 am-1:12 pm

Nonstop2h 51m

$59

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

mar. 3/11

6:00 am-8:50 am

Nonstop2h 50m

$86

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

mar. 3/18

11:42 am-2:40 pm

Nonstop2h 58m

$89

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/12

Showing 1-10 of 14 results
1
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Compare providers for flights from Ontario to Seattle

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to Seattle in February.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy3 starsTrust Score*2 stars
Kiwi.comPrice Accuracy3 starsTrust Score*2 stars
CheapfaremartPrice Accuracy-Trust Score*3 stars
CheapOairPrice Accuracy1 starTrust Score*3 stars
PricelinePrice Accuracy1 starTrust Score*3 stars
MytripPrice Accuracy3 starsTrust Score*3 stars
Justfly.comPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Ontario-Seattle flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Seattle flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Seattle flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-Seattle flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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.

Travel insights for flights from Ontario to Seattle

Get recent, data-driven insights about flights from Ontario to Seattle including ideal travel times, pricing trends, and more.

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

Use this chart to determine the optimal time to book a round-trip flight from Ontario to Seattle. Price data was last updated on February 7, 2025.

To ensure you get the cheapest price possible for a flight from Ontario to Seattle, you should look to book at least 78 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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

Currently, January is the cheapest month in which you can book a flight from Ontario to Seattle (average of $238). Flying from Ontario to Seattle in July is currently the most expensive (average of $411). 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 ONT 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 febrero 13, 2025.

It’s typically best to fly out from Ontario to Seattle in the morning. Doing so could potentially save you 41% on the flight price compared to flying at noon, which is usually more expensive.

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

Use this chart to determine the cheapest time to fly round-trip from Ontario to Seattle. Price data was last updated on February 10, 2025.

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

Weekly flight availability from 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 febrero 13, 2025.

The most flights from ONT to SEA are scheduled on a Thursday (16 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (5 on average).

Rainfall in Seattle by month

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

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

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 febrero 13, 2025.
Read reviews from past customers who have flown Southwest, Alaska Airlines and Delta 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.
Southwest
8.1
Very good
4,467 reviews

Comfort

8.1

Crew

8.7

Food

7.1

Boarding

8.2

Entertainment

7.6

Overall

8.1

Reviews

1 / 20

10.0
Excellent

Tim,Jul 2024

DEN - SEA

Sheila did great! First time I have ever seen all three people in an exit row get out and read the safety information card AFTER the briefing. I like the boarding process. It seems a shame to UN-differentiate SW because of abuse of the early boarding process.

Southwest
8.1
Very good
4,467 reviews
Southwest
8.1
Very good
4,467 reviews

Comfort

8.1

Crew

8.7

Food

7.1

Boarding

8.2

Entertainment

7.6

Overall

8.1

Reviews

1 / 20

10.0
Excellent

Tim,Jul 2024

DEN - SEA

Sheila did great! First time I have ever seen all three people in an exit row get out and read the safety information card AFTER the briefing. I like the boarding process. It seems a shame to UN-differentiate SW because of abuse of the early boarding process.

Alaska Airlines
8.0
Very good
9,694 reviews
Southwest
8.1
Very good
4,467 reviews

Comfort

8.1

Crew

8.7

Food

7.1

Boarding

8.2

Entertainment

7.6

Overall

8.1

Reviews

1 / 20

10.0
Excellent

Tim,Jul 2024

DEN - SEA

Sheila did great! First time I have ever seen all three people in an exit row get out and read the safety information card AFTER the briefing. I like the boarding process. It seems a shame to UN-differentiate SW because of abuse of the early boarding process.

Delta
8.0
Very good
8,316 reviews
Southwest
8.1
Very good
4,467 reviews

Comfort

8.1

Crew

8.7

Food

7.1

Boarding

8.2

Entertainment

7.6

Overall

8.1

Reviews

1 / 20

10.0
Excellent

Tim,Jul 2024

DEN - SEA

Sheila did great! First time I have ever seen all three people in an exit row get out and read the safety information card AFTER the briefing. I like the boarding process. It seems a shame to UN-differentiate SW because of abuse of the early boarding process.

Hawaiian Airlines
7.9
Good
2,318 reviews
Southwest
8.1
Very good
4,467 reviews

Comfort

8.1

Crew

8.7

Food

7.1

Boarding

8.2

Entertainment

7.6

Overall

8.1

Reviews

1 / 20

10.0
Excellent

Tim,Jul 2024

DEN - SEA

Sheila did great! First time I have ever seen all three people in an exit row get out and read the safety information card AFTER the briefing. I like the boarding process. It seems a shame to UN-differentiate SW because of abuse of the early boarding process.

United Airlines
7.4
Good
8,831 reviews
Southwest
8.1
Very good
4,467 reviews

Comfort

8.1

Crew

8.7

Food

7.1

Boarding

8.2

Entertainment

7.6

Overall

8.1

Reviews

1 / 20

10.0
Excellent

Tim,Jul 2024

DEN - SEA

Sheila did great! First time I have ever seen all three people in an exit row get out and read the safety information card AFTER the briefing. I like the boarding process. It seems a shame to UN-differentiate SW because of abuse of the early 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 airports do I use to fly from Ontario to Seattle?

    If you wish to fly to Seattle from Ontario, then you need to book flights from Ontario to Seattle/Tacoma Intl. There are 9 flights from Ontario (ONT) to Seattle/Tacoma Intl (SEA) per day to choose from. Flights to Seattle from Ontario are available from 5 different airlines, which means you should have some options if you want to compare airfare deals. 2h 36m is how long a nonstop flight from Ontario to Seattle/Tacoma Intl typically takes.

  • How popular is this Ontario to Seattle flight route?

    The Ontario to Seattle/Tacoma Intl flight path was viewed by 169 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

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

    Cheapflights users have booked flights from Ontario to Seattle round-trip from $92. Other airlines that can offer you cheap pricing are Alaska Airlines, from $177, and Delta, from $197. You may be able to fly from Ontario to Seattle for 51% less than the average price by searching for these airlines.

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

    The cheapest airlines for a one-way flight from Ontario to Seattle are Frontier ($59), Hawaiian Airlines ($86), and Delta ($89).

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

    Consider SkyWest Airlines (91%), Horizon Air (91%) or Delta (91%) when booking your flight. These represent the most reliable airlines when flying from Ontario to Seattle.

  • What are the cheapest flights from Ontario to Seattle?

    While on average a flight from Ontario to Seattle is generally $660, our data shows the cheapest flight currently is $54. When looking at the most popular route, (Ontario - Seattle/Tacoma Intl), you can expect to pay $83 for that flight.

  • 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 Ontario to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Ontario to Seattle (average of $238). Flying from Ontario to Seattle in July is currently the most expensive (average of $411). 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 Ontario?

Book flights to Ontario if you plan to visit one of these locations
SeaTac
Tukwila
Renton
Tacoma
Lacey
Ocean Shores
Leavenworth
Olympia
Federal Way
Centralia
Marysville
Cle Elum
Mukilteo
Aberdeen
Lakewood
Issaquah
Shoreline
Lynnwood
Shelton
Silverdale

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Ontario to Seattle

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Ontario to Seattle

Discover the top 5 airlines that operate flights from Ontario to Seattle. 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 2,558,603 searches. Data last updated febrero 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$62Average$140FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$71Average$130FlexibilityNo cancel feeOn-time65%
DeltaCheapest$106Average$251FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$134Average$259FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$186Average$366FlexibilityNo cancel feeOn-time63%
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