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Cheap flights from Seattle to Los Angeles from C$ 109

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Seattle to Los Angeles departing on 12/10. 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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Find the cheapest flights from Seattle to Los Angeles

Cheap round-trip flights

Frontier Logo
12:58 p.m. - 11:50 p.m.SEA-ONT
10h 52m1 stop
Frontier Logo
6:53 a.m. - 12:13 p.m.ONT-SEA
29h 20m1 stop
C$ 200Frontier
Find Deal
Sat, 8 Nov - Tue, 11 Nov
Frontier Logo
6:12 a.m. - 7:53 a.m.SEA-ONT
25h 41m1 stop
Frontier Logo
7:04 a.m. - 7:33 a.m.ONT-SEA
24h 29m1 stop
C$ 231Frontier
Find Deal
Sun, 28 Sep - Sat, 11 Oct
Alaska Airlines Logo
9:51 a.m. - 12:37 p.m.SEA-ONT
2h 46mdirect
Alaska Airlines Logo
6:00 a.m. - 8:45 a.m.ONT-SEA
2h 45mdirect
C$ 245Alaska Airlines
Find Deal
Wed, 15 Oct - Wed, 22 Oct
Southwest Logo
10:10 a.m. - 5:00 p.m.SEA-ONT
6h 50m1 stop
Southwest Logo
3:50 p.m. - 10:45 p.m.ONT-SEA
6h 55m2 stops
C$ 251Southwest
Find Deal
Wed, 15 Oct - Wed, 22 Oct
Delta Logo
2:24 p.m. - 5:10 p.m.SEA-ONT
2h 46mdirect
Delta Logo
7:35 a.m. - 10:35 a.m.ONT-SEA
3h 00mdirect
C$ 258Delta
Find Deal
Wed, 22 Oct - Mon, 27 Oct
Southwest Logo
7:05 a.m. - 1:00 p.m.SEA-ONT
5h 55m1 stop
Southwest Logo
3:50 p.m. - 10:45 p.m.ONT-SEA
6h 55m2 stops
C$ 265Southwest
Find Deal
Sat, 25 Oct - Tue, 28 Oct
Hawaiian Airlines Logo
9:25 p.m. - 12:03 a.m.SEA-ONT
2h 38mdirect
Hawaiian Airlines Logo
6:00 a.m. - 8:50 a.m.ONT-SEA
2h 50mdirect
C$ 272Hawaiian Airlines
Find Deal
Thu, 23 Oct - Sun, 26 Oct
Delta Logo
7:55 p.m. - 10:41 p.m.SEA-ONT
2h 46mdirect
Delta Logo
7:35 a.m. - 10:35 a.m.ONT-SEA
3h 00mdirect
C$ 275Delta
Find Deal
Fri, 24 Oct - Mon, 27 Oct
Alaska Airlines Logo
11:20 a.m. - 5:42 p.m.SEA-ONT
6h 22m1 stop
Alaska Airlines Logo
6:00 p.m. - 10:24 p.m.ONT-SEA
4h 24m1 stop
C$ 285Alaska Airlines
Find Deal
Fri, 27 Feb - Sat, 28 Feb
Hawaiian Airlines Logo
8:55 p.m. - 11:32 p.m.SEA-ONT
2h 37mdirect
Hawaiian Airlines Logo
6:00 a.m. - 8:50 a.m.ONT-SEA
2h 50mdirect
C$ 307Hawaiian Airlines
Find Deal
Fri, 7 Nov - Sat, 8 Nov

Delta flights from Seattle to Ontario

Our best Delta deals on Seattle to Ontario flight tickets
Delta
22 Oct
SEA2:24 p.m.Seattle/Tacoma Intl
2h 46m
ONT5:10 p.m.Ontario
27 Oct
ONT7:35 a.m.Ontario
3h 00m
SEA10:35 a.m.Seattle/Tacoma Intl
C$ 258
Find similar
Delta
24 Oct
SEA7:55 p.m.Seattle/Tacoma Intl
2h 46m
ONT10:41 p.m.Ontario
27 Oct
ONT7:35 a.m.Ontario
3h 00m
SEA10:35 a.m.Seattle/Tacoma Intl
C$ 275
Find similar
Delta
14 Oct
SEA9:29 a.m.Seattle/Tacoma Intl
14h 10m
2 stops
ONT11:39 p.m.Ontario
28 Oct
ONT11:48 a.m.Ontario
2h 57m
SEA2:45 p.m.Seattle/Tacoma Intl
C$ 300
Find similar

Alaska Airlines flights from Seattle to Ontario

Our best Alaska Airlines deals on Seattle to Ontario flight tickets
Alaska Airlines
15 Oct
SEA9:51 a.m.Seattle/Tacoma Intl
2h 46m
ONT12:37 p.m.Ontario
22 Oct
ONT6:00 a.m.Ontario
2h 45m
SEA8:45 a.m.Seattle/Tacoma Intl
C$ 245
Find similar
Alaska Airlines
27 Feb
SEA11:20 a.m.Seattle/Tacoma Intl
6h 22m
1 stop
ONT5:42 p.m.Ontario
28 Feb
ONT6:00 p.m.Ontario
4h 24m
1 stop
SEA10:24 p.m.Seattle/Tacoma Intl
C$ 285
Find similar
Alaska Airlines
28 Oct
SEA5:20 a.m.Seattle/Tacoma Intl
4h 38m
1 stop
ONT9:58 a.m.Ontario
15 Nov
ONT11:59 a.m.Ontario
2h 51m
SEA2:50 p.m.Seattle/Tacoma Intl
C$ 286
Find similar

momondo 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, momondo users made 96,600 searches. Data last updated 16 September 2025.
Use the filters below to find and compare flights from Seattle to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 8/11

12:58 p.m.-11:50 p.m.

1 stop10h 52m

Ontario

Tue 11/11

6:53 a.m.-12:13 p.m.

1 stop29h 20m

C$ 200

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sun 28/9

6:12 a.m.-7:53 a.m.

1 stop25h 41m

Ontario

Sat 11/10

7:04 a.m.-7:33 a.m.

1 stop24h 29m

C$ 231

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Wed 15/10

9:51 a.m.-12:37 p.m.

Nonstop2h 46m

Ontario

Wed 22/10

6:00 a.m.-8:45 a.m.

Nonstop2h 45m

C$ 245

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Wed 15/10

10:10 a.m.-5:00 p.m.

1 stop6h 50m

Ontario

Wed 22/10

3:50 p.m.-10:45 p.m.

2 stops6h 55m

C$ 251

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Wed 22/10

2:24 p.m.-5:10 p.m.

Nonstop2h 46m

Ontario

Mon 27/10

7:35 a.m.-10:35 a.m.

Nonstop3h 00m

C$ 258

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 25/10

7:05 a.m.-1:00 p.m.

1 stop5h 55m

Ontario

Tue 28/10

3:50 p.m.-10:45 p.m.

2 stops6h 55m

C$ 265

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 23/10

9:25 p.m.-12:03 a.m.

Nonstop2h 38m

Ontario

Sun 26/10

6:00 a.m.-8:50 a.m.

Nonstop2h 50m

C$ 272

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 24/10

7:55 p.m.-10:41 p.m.

Nonstop2h 46m

Ontario

Mon 27/10

7:35 a.m.-10:35 a.m.

Nonstop3h 00m

C$ 275

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 27/2

11:20 a.m.-5:42 p.m.

1 stop6h 22m

Ontario

Sat 28/2

6:00 p.m.-10:24 p.m.

1 stop4h 24m

C$ 285

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 7/11

8:55 p.m.-11:32 p.m.

Nonstop2h 37m

Ontario

Sat 8/11

6:00 a.m.-8:50 a.m.

Nonstop2h 50m

C$ 307

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Los Angeles from

How to get the cheapest flight ticket from Seattle to Ontario

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

What is the cheapest month to fly to Ontario?

The month of October is, on average, the cheapest month to fly to Ontario from Seattle, with most prices found around C$ 245. The month of September is another great option to travel to Ontario, with average flight prices from Seattle averaging around C$ 258.

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

On average, the least expensive day to fly to Ontario from Seattle is on a Monday. momondo users have found tickets for Monday departures for as low as C$ 219. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from Seattle because it is more convenient for both business and leisure travellers. As a result, prices tend to be around C$ 293.

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

Our data shows that the cheapest Seattle to Ontario flights are usually those with departure times in the morning. Our users have found flights to Ontario in the morning for as low as C$ 219. Try not to purchase tickets at noon because they tend to be around C$ 291. Of course, these prices can vary depending on the time of year and what airport you fly to.

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

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

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

You are more likely to see cheaper flights to Ontario from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to Ontario for around C$ 297 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Ontario from Seattle for as low as C$ 232 on momondo.

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

There is only 1 cabin class available to choose from on Seattle/Tacoma Intl to Ontario flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have Seattle to Ontario flight prices changed over time?

As of September 2025, prices for Seattle to Ontario flights are approximately 15% cheaper when compared to flights at the same time last year.

When to book flights from Seattle to Ontario

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

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

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

Best price found

C$ 286

Fastest flight time

2h 34m

Direct flights

Every day

Airports in Ontario

1 airport
The best one-way flight to Ontario from Seattle in the past 72 hours is C$ 286. The best round-trip flight deal from Seattle to Ontario found on momondo in the last 72 hours is C$ 259.
The fastest flight from Seattle to Ontario takes 2h 34m
Direct flights go from Seattle to Ontario every day.
There is 1 airport near Ontario: Ontario (ONT)
Search flight deals

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

    A flight from Seattle/Tacoma Intl to Ontario will travel around 1555.6 km. Flights usually cover this in 2h 32m, depending on flying conditions and air traffic around both airports.

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

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

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

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

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to Ontario Airport.

  • What documentation or ID do you need to fly to Ontario Airport?

    The travel and health documents you'll need for your trip to Ontario Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Ontario Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

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

  • What is the most popular airline from Seattle to Ontario?

Best airlines flying from Seattle to Ontario

Compare and see reviews for airlines that fly from Seattle to Ontario with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom C$ 117Free CancellationRating
5.8
3,174 reviews
Search Frontier flights
Alaska AirlinesPriceFrom C$ 216Free CancellationRating
8.0
10,000 reviews
Search Alaska Airlines flights

  • Alaska Airlines Flights From Seattle to Ontario

    Across 15 Alaska Airlines flights from Seattle to Ontario this week, the average price was C$ 221, with the best Alaska Airlines deals starting from C$ 157 round-trip. 10,000 users have rated Alaska Airlines on momondo, with an average score of 8.0/10.

Why use momondo?

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

To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to Ontario from Seattle.

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

momondo does allow users to show only those flights to Ontario from Seattle which offer a flexible booking policy as well as other useful filters and features.

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

momondo provides multiple filters to help you find the best flight to Ontario from Seattle. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

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

Price alerts on flights to Ontario from Seattle 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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