What is the most punctual flight time for Ontario to Seattle flights?

Generally, flights departing at night tend to experience fewer delays. Flights in the evening have, in the past, seen delays more frequently in comparison.

How many flights depart from Ontario to Seattle on average per week?

As of February 2026, there are 67 flights per week flying from Ontario to Seattle. The most common day of the week flights depart is Sun, with 22% of flights taking off on this day.

How often are flights from Ontario to Seattle delayed?

Historically, on average around 9% of flights between Ontario and Seattle have experienced a delay on any given week. The average delay length over the past 12 months has been 130 minutes.

How many flights depart from Ontario to Seattle on average per day?

The number of flights available between Ontario and Seattle is 9 per day as of February 2026. The most frequent departure time is 7:00AM, with 73% of daily flights leaving at noon.

Which airline has the best punctuality record on Ontario to Seattle flights?

According to our data, Delta have had the least number of delays on this route over the last 12 months; with about 4% of their flights experiencing any sort of delay.

What day of the week experiences the fewest flight delays on this route?

Wednesday is statistically the day of the week which experiences the fewest number of delays on this flight route. Friday has historically seen more delays on average compared to the rest of the week.

What is the cheapest airline that flies from Ontario to Seattle/Tacoma Intl?

Alaska Airlines, Delta, and Southwest are the most popular carriers operating from Ontario to Seattle/Tacoma Intl

What airlines fly to Seattle?

Alaska Airlines, Frontier and Delta are the top three most popular airlines that fly to Seattle from Ontario according to our data. Alaska Airlines is the first choice among our users, with 45% of people opting to fly with this airline when traveling to Seattle. Keep in mind that there are 9 different airlines that fly to Seattle on a routine basis, so you have a few additional options to choose from.

When did momondo last update prices for flights from Ontario Airport to Seattle/Tacoma Intl Airport?

Prices for flights from Ontario Airport to Seattle/Tacoma Intl Airport are updated daily.

How many operators does momondo search for flights from Ontario Airport to Seattle/Tacoma Intl Airport?

The number of operators available for flights from Ontario Airport to Seattle/Tacoma Intl Airport is 5 as of February 2026.

How old do you have to be to fly from Ontario 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 Ontario Airport to Seattle/Tacoma Intl Airport.

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

The necessary travel and health documents for your Seattle/Tacoma Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

$89 Cheap Flights from Ontario to Seattle in 2026

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Find the cheapest flights from Ontario to Seattle

Round-trip

One-way

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Cheap round-trip flights

Enter your travel dates to find the best prices.

7:22 pm - 8:51 am

ONT

SEA

13h 29m

1 stop

7:33 pm - 1:11 pm

SEA

ONT

17h 38m

1 stop

$131Frontier

Thu, Feb 26 - Tue, Mar 3

2:06 pm - 8:20 pm

ONT

SEA

6h 14m

1 stop

9:35 pm - 8:06 am

SEA

ONT

10h 31m

1 stop

$145Frontier

Thu, Mar 12 - Sun, Mar 22

6:05 am - 10:55 am

ONT

SEA

28h 50m

1 stop

1:16 pm - 11:59 pm

SEA

ONT

10h 43m

1 stop

$152Frontier

Thu, Feb 26 - Sat, Feb 28

12:02 pm - 2:52 pm

ONT

SEA

2h 50mnonstop

8:30 am - 11:08 am

SEA

ONT

2h 38mnonstop

$153Hawaiian Airlines

Thu, Feb 26 - Sun, Mar 1

3:24 pm - 8:51 am

ONT

SEA

17h 27m

1 stop

7:33 pm - 1:11 pm

SEA

ONT

17h 38m

1 stop

$155Frontier

Thu, Feb 26 - Tue, Mar 3

2:06 pm - 8:20 pm

ONT

SEA

6h 14m

1 stop

9:35 pm - 8:06 am

SEA

ONT

10h 31m

1 stop

$156Frontier

Thu, Mar 12 - Sun, Mar 15

4:02 pm - 6:52 pm

ONT

SEA

2h 50mnonstop

8:56 pm - 11:32 pm

SEA

ONT

2h 36mnonstop

$157Alaska Airlines

Sat, Mar 7 - Sat, Mar 14

12:02 pm - 2:52 pm

ONT

SEA

2h 50mnonstop

8:56 pm - 11:32 pm

SEA

ONT

2h 36mnonstop

$159Hawaiian Airlines

Sat, Feb 28 - Mon, Mar 2

12:59 am - 9:27 am

ONT

SEA

8h 28m

1 stop

4:20 pm - 11:55 pm

SEA

ONT

7h 35m

1 stop

$160Frontier

Fri, Apr 17 - Sun, Apr 19

12:02 pm - 2:52 pm

ONT

SEA

2h 50mnonstop

8:30 am - 11:08 am

SEA

ONT

2h 38mnonstop

$161Hawaiian Airlines

Sat, Feb 28 - Mon, Mar 2

Delta flights from Ontario to Seattle

Our best Delta deals on Ontario to Seattle flight tickets

Delta

Mar 5

ONT7:30 amOntario

3h 04m

SEA10:34 amSeattle/Tacoma Intl

Mar 9

SEA8:30 amSeattle/Tacoma Intl

2h 47m

ONT11:17 amOntario

$177

Delta

Mar 9

ONT6:00 amOntario

2h 54m

SEA8:54 amSeattle/Tacoma Intl

Mar 10

SEA2:30 pmSeattle/Tacoma Intl

2h 42m

ONT5:12 pmOntario

$207

Delta

Mar 20

ONT6:00 amOntario

2h 55m

SEA8:55 amSeattle/Tacoma Intl

Mar 22

SEA7:50 pmSeattle/Tacoma Intl

2h 44m

ONT10:34 pmOntario

$208

Frontier flights from Ontario to Seattle

Our best Frontier deals on Ontario to Seattle flight tickets

Frontier

Feb 26

ONT3:24 pmOntario

17h 27m

1 stop

SEA8:51 amSeattle/Tacoma Intl

Mar 1

SEA9:23 pmSeattle/Tacoma Intl

15h 48m

1 stop

ONT1:11 pmOntario

$131

Frontier

Mar 12

ONT2:06 pmOntario

6h 14m

1 stop

SEA8:20 pmSeattle/Tacoma Intl

Mar 22

SEA9:35 pmSeattle/Tacoma Intl

10h 31m

1 stop

ONT8:06 amOntario

$145

Frontier

Feb 26

ONT6:05 amOntario

28h 50m

1 stop

SEA10:55 amSeattle/Tacoma Intl

Feb 28

SEA1:16 pmSeattle/Tacoma Intl

10h 43m

1 stop

ONT11:59 pmOntario

$152

Fly from

Fly to

Route

Depart

Return

Price

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 2/26

7:22 pm-8:51 am

1 stop13h 29m

Seattle/Tacoma Intl

Tue 3/3

7:33 pm-1:11 pm

1 stop17h 38m

$131

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 3/12

2:06 pm-8:20 pm

1 stop6h 14m

Seattle/Tacoma Intl

Sun 3/22

9:35 pm-8:06 am

1 stop10h 31m

$145

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 2/26

6:05 am-10:55 am

1 stop28h 50m

Seattle/Tacoma Intl

Sat 2/28

1:16 pm-11:59 pm

1 stop10h 43m

$152

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 2/26

12:02 pm-2:52 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Sun 3/1

8:30 am-11:08 am

Nonstop2h 38m

$153

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 2/26

3:24 pm-8:51 am

1 stop17h 27m

Seattle/Tacoma Intl

Tue 3/3

7:33 pm-1:11 pm

1 stop17h 38m

$155

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 3/12

2:06 pm-8:20 pm

1 stop6h 14m

Seattle/Tacoma Intl

Sun 3/15

9:35 pm-8:06 am

1 stop10h 31m

$156

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 3/7

4:02 pm-6:52 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Sat 3/14

8:56 pm-11:32 pm

Nonstop2h 36m

$157

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 2/28

12:02 pm-2:52 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Mon 3/2

8:56 pm-11:32 pm

Nonstop2h 36m

$159

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Fri 4/17

12:59 am-9:27 am

1 stop8h 28m

Seattle/Tacoma Intl

Sun 4/19

4:20 pm-11:55 pm

1 stop7h 35m

$160

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 2/28

12:02 pm-2:52 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Mon 3/2

8:30 am-11:08 am

Nonstop2h 38m

$161

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How to get the cheapest flight ticket from Ontario 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

Prices

Airlines

Delays

Other information

What is the cheapest month to fly to Seattle?

In general, March is the cheapest month to fly from Ontario to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $187. If you don’t want to visit Seattle in March, then you should wait until May to fly from Ontario, when ticket prices are also cheap, with an average price of $197.

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

On average, the least expensive day to fly to Seattle from Ontario is on a Friday. momondo users have found tickets for Friday departures for as low as $275. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Tuesday is the most expensive day to depart from Ontario because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $374.

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

Flying to Seattle from Ontario in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $242 when looking at flights departing in the afternoon. Flights to Seattle are more costly in the morning, with an average ticket price of $343. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

What is the cheapest Ontario to Seattle/Tacoma Intl flight route?

Fly from Ontario to Seattle/Tacoma Intl for the best Ontario - Seattle/Tacoma Intl flight prices

How far in advance should I book a flight to Seattle?

You are more likely to see cheaper flights to Seattle from Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $217 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from Ontario for as low as $173 on momondo.

What cabin class options are available on Ontario to Seattle/Tacoma Intl flights?

There are 4 cabin classes available to choose from on Ontario to Seattle/Tacoma Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Ontario to Seattle flights?

You could potentially save up to 1% on your flight if you consider stops on a Ontario to Seattle flight.

How have Ontario to Seattle flight prices changed over time?

As of February 2026, prices for Ontario to Seattle flights are approximately 38% cheaper when compared to flights at the same time last year.

When to book flights from Ontario to Seattle

Are you open to changing your travel dates? Check out the ideal times to fly from Ontario to Seattle according to our flight data. Find out which month and days have the cheapest flights.

Estimated round-trip price

Cheap Ontario to Seattle (ONT to SEA) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Ontario to Seattle

Best Price Found	$152
Fastest flight time	2h 42m
Direct flights	Every day
Airports in Seattle	1 airport

The best one-way flight to Seattle from Ontario in the past 72 hours is $152. The best round-trip flight deal from Ontario to Seattle found on momondo in the last 72 hours is $248.

The fastest flight from Ontario to Seattle takes 2h 42m

Direct flights go from Ontario to Seattle every day.

There is 1 airport in Seattle. From Ontario there are direct flights to Seattle/Tacoma Intl (SEA).

Search flight deals

How far is Ontario to Seattle/Tacoma Intl by plane?
The straight-line distance from Ontario to Seattle/Tacoma Intl is 966.6 mi. By plane, this route typically takes 2h 42m.
When did momondo last update prices for flights from Ontario Airport to Seattle/Tacoma Intl Airport?
Prices for flights from Ontario Airport to Seattle/Tacoma Intl Airport are updated daily.
How many operators does momondo search for flights from Ontario Airport to Seattle/Tacoma Intl Airport?
The number of operators available for flights from Ontario Airport to Seattle/Tacoma Intl Airport is 5 as of February 2026.
How old do you have to be to fly from Ontario 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 Ontario Airport to Seattle/Tacoma Intl Airport.
What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?
The necessary travel and health documents for your Seattle/Tacoma Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.
What is the most popular plane model from Ontario to Seattle?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from Ontario to Seattle is Boeing 737-800 Passenger/BBJ2 (winglets) (26.18% of total bookings). The next most popular plane models are Airbus A320neo (10.19%), Boeing 737-900 Passenger/BBJ3 (winglets) (9.16%), and Boeing 737 MAX 9 (6.66%).
What is the most popular airline from Ontario to Seattle?
Based on momondo bookings for this flight route, the most popular airline on flight routes from Ontario to Seattle is Frontier (40% of total bookings). The next most popular airlines are Alaska Airlines (33%), Delta (19%), and Hawaiian Airlines (8%).

Best airlines flying from Ontario to Seattle

Compare and see reviews for airlines that fly from Ontario to Seattle with momondo

Airline	Rating	Free Cancellation	Price
Frontier	PriceFrom $80	Free Cancellation	Rating 5.7 3,052 reviews	Search Frontier flights
Hawaiian Airlines	PriceFrom $88	Free Cancellation	Rating 7.8 2,829 reviews	Search Hawaiian Airlines flights
Delta	PriceFrom $99	Free Cancellation	Rating 7.9 8,172 reviews	Search Delta flights
Alaska Airlines	PriceFrom $140	Free Cancellation	Rating 8.0 11,850 reviews	Search Alaska Airlines flights
Southwest	PriceFrom $150	Free Cancellation	Rating 8.0 4,280 reviews	Search Southwest flights

Alaska Airlines Flights From Ontario to Seattle
Alaska Airlines flight deals from Ontario to Seattle start from $140 round-trip. Over the 10 Alaska Airlines flights for this route in a normal week, average airfare is usually $269 round-trip - but some users have found much cheaper deals with momondo.
Delta Flights From Ontario to Seattle
$99 is the best Delta flight deal from Ontario to Seattle found on momondo over the last 72 hours. The average Delta ticket price found was closer to $250, however, with flight time and availability significantly affecting the price. Delta (7.9/10 from 8,172 user reviews) flies into Seattle from Ontario 10 times in an average week so prices can vary.

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 Ontario to Seattle?

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from Ontario to Seattle. momondo saves you time and could save you money on your trip.

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

Yes. momondo enables you to select and highlight flights to Seattle from Ontario with this policy.

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

momondo helps you find the best flight between Ontario and Seattle by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

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

Price alerts on flights to Seattle from Ontario are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

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Pullman Moscow Regional Airport

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Cheap flights from Ontario to Seattle from $89

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to Seattle departing on 4/4. 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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Delta flights from Ontario to Seattle

Our best Delta deals on Ontario to Seattle flight tickets

Frontier flights from Ontario to Seattle

Our best Frontier deals on Ontario to Seattle flight tickets

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

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How to get the cheapest flight ticket from Ontario to Seattle

What is the cheapest month to fly to Seattle?

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

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

What is the cheapest Ontario to Seattle/Tacoma Intl flight route?

Fly from Ontario to Seattle/Tacoma Intl for the best Ontario - Seattle/Tacoma Intl flight prices

How far in advance should I book a flight to Seattle?

What cabin class options are available on Ontario to Seattle/Tacoma Intl flights?

There are 4 cabin classes available to choose from on Ontario to Seattle/Tacoma Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Ontario to Seattle flights?

You could potentially save up to 1% on your flight if you consider stops on a Ontario to Seattle flight.

How have Ontario to Seattle flight prices changed over time?

As of February 2026, prices for Ontario to Seattle flights are approximately 38% cheaper when compared to flights at the same time last year.

What is the cheapest airline that flies from Ontario to Seattle/Tacoma Intl?

Alaska Airlines, Delta, and Southwest are the most popular carriers operating from Ontario to Seattle/Tacoma Intl

What airlines fly to Seattle?

How often are flights from Ontario to Seattle delayed?

Historically, on average around 9% of flights between Ontario and Seattle have experienced a delay on any given week. The average delay length over the past 12 months has been 130 minutes.

What is the most punctual flight time for Ontario to Seattle flights?

Generally, flights departing at night tend to experience fewer delays. Flights in the evening have, in the past, seen delays more frequently in comparison.

What day of the week experiences the fewest flight delays on this route?

Wednesday is statistically the day of the week which experiences the fewest number of delays on this flight route. Friday has historically seen more delays on average compared to the rest of the week.

Which airline has the best punctuality record on Ontario to Seattle flights?

According to our data, Delta have had the least number of delays on this route over the last 12 months; with about 4% of their flights experiencing any sort of delay.

How many flights depart from Ontario to Seattle on average per day?

The number of flights available between Ontario and Seattle is 9 per day as of February 2026. The most frequent departure time is 7:00AM, with 73% of daily flights leaving at noon.

How many flights depart from Ontario to Seattle on average per week?

As of February 2026, there are 67 flights per week flying from Ontario to Seattle. The most common day of the week flights depart is Sun, with 22% of flights taking off on this day.

When to book flights from Ontario to Seattle

Cheap Ontario to Seattle (ONT to SEA) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Ontario to Seattle

Best Price Found

Fastest flight time

Direct flights

Airports in Seattle

How far is Ontario to Seattle/Tacoma Intl by plane?

When did momondo last update prices for flights from Ontario Airport to Seattle/Tacoma Intl Airport?

How many operators does momondo search for flights from Ontario Airport to Seattle/Tacoma Intl Airport?

How old do you have to be to fly from Ontario Airport to Seattle/Tacoma Intl Airport?

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

What is the most popular plane model from Ontario to Seattle?

What is the most popular airline from Ontario to Seattle?

Best airlines flying from Ontario to Seattle

Compare and see reviews for airlines that fly from Ontario to Seattle with momondo

Alaska Airlines Flights From Ontario to Seattle

Delta Flights From Ontario to Seattle

Traveling to a place near Seattle?

Why use momondo?

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

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

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

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

An easier way to manage your Seattle trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to the United States

Airports servicing Washington