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Cheap flights from Seattle to Los Angeles from C$ 121

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 17/2. 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

Enter your travel dates to find the best prices.
Alaska Airlines Logo
8:30 a.m. - 11:08 a.m.
SEA
-
ONT
2h 38mdirect
Alaska Airlines Logo
12:02 p.m. - 2:52 p.m.
ONT
-
SEA
2h 50mdirect
C$ 213Alaska Airlines
Sat, 21 Feb - Wed, 25 Feb
Frontier Logo
4:20 p.m. - 11:55 p.m.
SEA
-
ONT
7h 35m
1 stop
Frontier Logo
9:02 a.m. - 4:41 p.m.
ONT
-
SEA
7h 39m
1 stop
C$ 219Frontier
Thu, 30 Apr - Mon, 4 May
Alaska Airlines Logo
8:56 p.m. - 11:32 p.m.
SEA
-
ONT
2h 36mdirect
Alaska Airlines Logo
12:02 p.m. - 2:52 p.m.
ONT
-
SEA
2h 50mdirect
C$ 227Alaska Airlines
Thu, 19 Feb - Tue, 24 Feb
Southwest Logo
9:30 a.m. - 2:55 p.m.
SEA
-
ONT
5h 25m
1 stop
Southwest Logo
7:20 a.m. - 12:10 p.m.
ONT
-
SEA
4h 50m
1 stop
C$ 240Southwest
Wed, 18 Feb - Tue, 24 Feb
Frontier Logo
4:20 p.m. - 11:55 p.m.
SEA
-
ONT
7h 35m
1 stop
Frontier Logo
9:02 a.m. - 4:41 p.m.
ONT
-
SEA
7h 39m
1 stop
C$ 248Frontier
Thu, 30 Apr - Mon, 4 May
Alaska Airlines Logo
12:30 p.m. - 3:08 p.m.
SEA
-
ONT
2h 38mdirect
Alaska Airlines Logo
6:14 a.m. - 9:09 a.m.
ONT
-
SEA
2h 55mdirect
C$ 254Alaska Airlines
Tue, 24 Feb - Sun, 1 Mar
Southwest Logo
7:15 a.m. - 2:00 p.m.
SEA
-
ONT
6h 45m
1 stop
Southwest Logo
9:00 a.m. - 5:20 p.m.
ONT
-
SEA
8h 20m
1 stop
C$ 261Southwest
Sat, 7 Mar - Fri, 13 Mar
Alaska Airlines Logo
8:30 a.m. - 11:08 a.m.
SEA
-
ONT
2h 38mdirect
Alaska Airlines Logo
6:14 a.m. - 9:09 a.m.
ONT
-
SEA
2h 55mdirect
C$ 267Alaska Airlines
Thu, 26 Feb - Sun, 1 Mar
Alaska Airlines Logo
8:10 p.m. - 7:14 p.m.
SEA
-
ONT
23h 04m
1 stop
Alaska Airlines Logo
12:02 p.m. - 2:52 p.m.
ONT
-
SEA
2h 50mdirect
C$ 272Alaska Airlines
Tue, 17 Feb - Tue, 24 Feb
Alaska Airlines Logo
9:24 p.m. - 11:59 p.m.
SEA
-
ONT
2h 35mdirect
Alaska Airlines Logo
4:22 p.m. - 8:58 p.m.
ONT
-
SEA
4h 36m
1 stop
C$ 274Alaska Airlines
Tue, 7 Apr - Wed, 15 Apr

United Airlines flights from Seattle to Ontario

Our best United Airlines deals on Seattle to Ontario flight tickets
United Airlines
17 Feb
SEA5:00 a.m.Seattle/Tacoma Intl
7h 43m
1 stop
ONT12:43 p.m.Ontario
20 Feb
ONT6:37 p.m.Ontario
4h 53m
1 stop
SEA11:30 p.m.Seattle/Tacoma Intl
C$ 341
United Airlines
10 Feb
SEA12:35 p.m.Seattle/Tacoma Intl
5h 08m
1 stop
ONT5:43 p.m.Ontario
21 Feb
ONT1:53 p.m.Ontario
7h 08m
1 stop
SEA9:01 p.m.Seattle/Tacoma Intl
C$ 474
United Airlines
5 Feb
SEA5:00 a.m.Seattle/Tacoma Intl
7h 47m
1 stop
ONT12:47 p.m.Ontario
5 Feb
ONT6:39 p.m.Ontario
6h 20m
1 stop
SEA12:59 a.m.Seattle/Tacoma Intl
C$ 479

Alaska Airlines flights from Seattle to Ontario

Our best Alaska Airlines deals on Seattle to Ontario flight tickets
Alaska Airlines
21 Feb
SEA8:30 a.m.Seattle/Tacoma Intl
2h 38m
ONT11:08 a.m.Ontario
25 Feb
ONT12:02 p.m.Ontario
2h 50m
SEA2:52 p.m.Seattle/Tacoma Intl
C$ 213
Alaska Airlines
19 Feb
SEA8:56 p.m.Seattle/Tacoma Intl
2h 36m
ONT11:32 p.m.Ontario
24 Feb
ONT12:02 p.m.Ontario
2h 50m
SEA2:52 p.m.Seattle/Tacoma Intl
C$ 227
Alaska Airlines
24 Feb
SEA12:30 p.m.Seattle/Tacoma Intl
2h 38m
ONT3:08 p.m.Ontario
1 Mar
ONT6:14 a.m.Ontario
2h 55m
SEA9:09 a.m.Seattle/Tacoma Intl
C$ 254

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 29 January 2026.
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 21/2

8:30 a.m.-11:08 a.m.

Nonstop2h 38m

Ontario

Wed 25/2

12:02 p.m.-2:52 p.m.

Nonstop2h 50m

C$ 213

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 30/4

4:20 p.m.-11:55 p.m.

1 stop7h 35m

Ontario

Mon 4/5

9:02 a.m.-4:41 p.m.

1 stop7h 39m

C$ 219

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 19/2

8:56 p.m.-11:32 p.m.

Nonstop2h 36m

Ontario

Tue 24/2

12:02 p.m.-2:52 p.m.

Nonstop2h 50m

C$ 227

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Wed 18/2

9:30 a.m.-2:55 p.m.

1 stop5h 25m

Ontario

Tue 24/2

7:20 a.m.-12:10 p.m.

1 stop4h 50m

C$ 240

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 30/4

4:20 p.m.-11:55 p.m.

1 stop7h 35m

Ontario

Mon 4/5

9:02 a.m.-4:41 p.m.

1 stop7h 39m

C$ 248

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 24/2

12:30 p.m.-3:08 p.m.

Nonstop2h 38m

Ontario

Sun 1/3

6:14 a.m.-9:09 a.m.

Nonstop2h 55m

C$ 254

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 7/3

7:15 a.m.-2:00 p.m.

1 stop6h 45m

Ontario

Fri 13/3

9:00 a.m.-5:20 p.m.

1 stop8h 20m

C$ 261

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 26/2

8:30 a.m.-11:08 a.m.

Nonstop2h 38m

Ontario

Sun 1/3

6:14 a.m.-9:09 a.m.

Nonstop2h 55m

C$ 267

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 17/2

8:10 p.m.-7:14 p.m.

1 stop23h 04m

Ontario

Tue 24/2

12:02 p.m.-2:52 p.m.

Nonstop2h 50m

C$ 272

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 7/4

9:24 p.m.-11:59 p.m.

Nonstop2h 35m

Ontario

Wed 15/4

4:22 p.m.-8:58 p.m.

1 stop4h 36m

C$ 274

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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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$ 254. The month of March is another great option to travel to Ontario, with average flight prices from Seattle averaging around C$ 255.

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 Sunday. momondo users have found tickets for Sunday departures for as low as C$ 167. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Friday 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$ 410.

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$ 215. Try not to purchase tickets at noon because they tend to be around C$ 382. 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$ 318 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$ 248 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.

Can stopping save me money on Seattle to Ontario flights?

No. A direct flight is the cheapest option for a flight between Seattle to Ontario.

How have Seattle to Ontario flight prices changed over time?

As of January 2026, prices for Seattle to Ontario flights are approximately 6% more expensive 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$ 476

Fastest flight time

2h 36m

Direct flights

Every day

Airports in Ontario

1 airport
The best flight deal from Seattle to Ontario found on momondo in the last 72 hours is C$ 476
The fastest flight from Seattle to Ontario takes 2h 36m
Direct flights go from Seattle to Ontario every day.
There is 1 airport in Ontario. From Seattle there are direct flights to 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 36m, 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$ 115Free CancellationRating
5.7
3,056 reviews
Search Frontier flights

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.

An easier way to manage your Ontario trip

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