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Cheap flights from Seattle to Los Angeles from $64

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 1/24. 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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Cheap round-trip flights

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Frontier Logo
11:06 am - 1:42 pm
SEA
-
ONT
2h 36mnonstop
Frontier Logo
10:45 am - 9:04 am
ONT
-
SEA
22h 19m1 stop
$123Frontier
Mon, Jan 5 - Wed, Jan 7
Frontier Logo
6:48 pm - 9:23 pm
SEA
-
ONT
2h 35mnonstop
Frontier Logo
2:34 pm - 7:51 pm
ONT
-
SEA
5h 17m1 stop
$125Frontier
Thu, Jan 8 - Thu, Jan 15
Frontier Logo
1:00 pm - 10:12 pm
SEA
-
ONT
9h 12m1 stop
Frontier Logo
5:15 pm - 8:08 pm
ONT
-
SEA
2h 53mnonstop
$126Frontier
Tue, Jan 6 - Thu, Jan 8
Frontier Logo
12:54 pm - 9:18 am
SEA
-
ONT
20h 24m1 stop
Frontier Logo
7:15 am - 11:19 am
ONT
-
SEA
28h 04m1 stop
$128Frontier
Sat, Jan 24 - Wed, Jan 28
Delta Logo
5:25 am - 12:16 pm
SEA
-
ONT
6h 51m1 stop
Delta Logo
7:30 am - 10:36 am
ONT
-
SEA
3h 06mnonstop
$129Delta
Sat, Jan 17 - Sun, Jan 18
Frontier Logo
6:48 pm - 9:23 pm
SEA
-
ONT
2h 35mnonstop
Frontier Logo
2:34 pm - 7:47 pm
ONT
-
SEA
5h 13m1 stop
$130Frontier
Thu, Jan 8 - Mon, Jan 12
Frontier Logo
6:48 pm - 9:23 pm
SEA
-
ONT
2h 35mnonstop
Frontier Logo
2:34 pm - 7:47 pm
ONT
-
SEA
5h 13m1 stop
$131Frontier
Thu, Jan 8 - Mon, Jan 12
Frontier Logo
1:11 pm - 7:10 pm
SEA
-
ONT
5h 59m1 stop
Frontier Logo
3:22 pm - 10:54 am
ONT
-
SEA
19h 32m1 stop
$133Frontier
Mon, Jan 26 - Mon, Feb 9
Alaska Airlines Logo
8:56 pm - 11:32 pm
SEA
-
ONT
2h 36mnonstop
Alaska Airlines Logo
12:02 pm - 2:52 pm
ONT
-
SEA
2h 50mnonstop
$138Alaska Airlines
Thu, Feb 19 - Sat, Feb 28
Delta Logo
5:25 am - 12:16 pm
SEA
-
ONT
6h 51m1 stop
Delta Logo
5:10 pm - 12:09 am
ONT
-
SEA
6h 59m1 stop
$139Delta
Thu, Jan 15 - Tue, Jan 20

Frontier flights from Seattle to Ontario

Our best Frontier deals on Seattle to Ontario flight tickets
Frontier
Jan 5
SEA11:06 amSeattle/Tacoma Intl
2h 36m
ONT1:42 pmOntario
Jan 7
ONT10:45 amOntario
22h 19m
1 stop
SEA9:04 amSeattle/Tacoma Intl
$123
Find similar
Frontier
Jan 8
SEA6:48 pmSeattle/Tacoma Intl
2h 35m
ONT9:23 pmOntario
Jan 15
ONT2:34 pmOntario
5h 17m
1 stop
SEA7:51 pmSeattle/Tacoma Intl
$125
Find similar
Frontier
Jan 24
SEA12:54 pmSeattle/Tacoma Intl
20h 24m
1 stop
ONT9:18 amOntario
Jan 28
ONT7:15 amOntario
28h 04m
1 stop
SEA11:19 amSeattle/Tacoma Intl
$128
Find similar

Southwest flights from Seattle to Ontario

Our best Southwest deals on Seattle to Ontario flight tickets
Southwest
Jan 17
SEA6:25 amSeattle/Tacoma Intl
4h 10m
1 stop
ONT10:35 amOntario
Jan 20
ONT11:10 amOntario
4h 50m
1 stop
SEA4:00 pmSeattle/Tacoma Intl
$151
Find similar
Southwest
Jan 17
SEA11:40 amSeattle/Tacoma Intl
6h 55m
2 stops
ONT6:35 pmOntario
Jan 20
ONT5:35 pmOntario
4h 15m
1 stop
SEA9:50 pmSeattle/Tacoma Intl
$156
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 832,500 searches. Data last updated December 18, 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

Mon 1/5

11:06 am-1:42 pm

Nonstop2h 36m

Ontario

Wed 1/7

10:45 am-9:04 am

1 stop22h 19m

$123

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 1/8

6:48 pm-9:23 pm

Nonstop2h 35m

Ontario

Thu 1/15

2:34 pm-7:51 pm

1 stop5h 17m

$125

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Tue 1/6

1:00 pm-10:12 pm

1 stop9h 12m

Ontario

Thu 1/8

5:15 pm-8:08 pm

Nonstop2h 53m

$126

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 1/24

12:54 pm-9:18 am

1 stop20h 24m

Ontario

Wed 1/28

7:15 am-11:19 am

1 stop28h 04m

$128

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sat 1/17

5:25 am-12:16 pm

1 stop6h 51m

Ontario

Sun 1/18

7:30 am-10:36 am

Nonstop3h 06m

$129

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 1/8

6:48 pm-9:23 pm

Nonstop2h 35m

Ontario

Mon 1/12

2:34 pm-7:47 pm

1 stop5h 13m

$130

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 1/8

6:48 pm-9:23 pm

Nonstop2h 35m

Ontario

Mon 1/12

2:34 pm-7:47 pm

1 stop5h 13m

$131

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Mon 1/26

1:11 pm-7:10 pm

1 stop5h 59m

Ontario

Mon 2/9

3:22 pm-10:54 am

1 stop19h 32m

$133

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 2/19

8:56 pm-11:32 pm

Nonstop2h 36m

Ontario

Sat 2/28

12:02 pm-2:52 pm

Nonstop2h 50m

$138

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 1/15

5:25 am-12:16 pm

1 stop6h 51m

Ontario

Tue 1/20

5:10 pm-12:09 am

1 stop6h 59m

$139

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?

In general, October is the cheapest month to fly from Seattle to Ontario. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $187. If you aren’t able to travel during the month of October, then book flights to Ontario from Seattle during March instead. Flights to Ontario in March, while not as cheap as those in October, still average around $193.

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

The cheapest day to depart on your flight to Ontario is on a Wednesday when prices can be found for as low as $214. This is often the case because there is less demand to fly during this day of the week. When flying out on a Saturday, the most expensive travel day of the week, you can expect to see flight prices from Seattle to Ontario for around $234.

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

At noon is the cheapest time of day to fly from Seattle to Ontario when you can find flight prices for as low as $196. Flying to Ontario at noon is an ideal time because this is during off-peak travel hours. If you have a flexible travel schedule, then try to avoid flying in the evening when prices are $249 on average. Flights to Ontario from Seattle in the evening are generally more expensive because this time of day is more convenient for travelers’ schedules.

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 $229 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 $185 on momondo.

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

There are 4 cabin classes 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 December 2025, prices for Seattle to Ontario flights are approximately 7% 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

$124

Fastest flight time

2h 33m

Direct flights

Every day

Airports in Ontario

1 airport
The best one-way flight to Ontario from Seattle in the past 72 hours is $124. The best round-trip flight deal from Seattle to Ontario found on momondo in the last 72 hours is $209.
The fastest flight from Seattle to Ontario takes 2h 33m
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?

    The distance between Seattle/Tacoma Intl and Ontario is about 966.6 mi. A reasonable flight in good conditions will take 2h 33m.

  • 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 are refreshed on a daily basis.

  • 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?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, 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 $68Free CancellationRating
5.8
3,081 reviews
Search Frontier flights
Hawaiian AirlinesPriceFrom $98Free CancellationRating
7.8
2,820 reviews
Search Hawaiian Airlines flights
SouthwestPriceFrom $113Free CancellationRating
7.9
4,250 reviews
Search Southwest flights
DeltaPriceFrom $119Free CancellationRating
7.9
8,008 reviews
Search Delta flights
Alaska AirlinesPriceFrom $157Free CancellationRating
8.0
11,478 reviews
Search Alaska Airlines flights

  • Alaska Airlines Flights From Seattle to Ontario

    Alaska Airlines flies from Seattle to Ontario around 4 times per week, with 11,478 momondo users rating the airline 8.0/10. The cheapest Alaska Airlines deal from Seattle to Ontario in the last 72 hours was $157 (round-trip), much lower than the average airfare cost of $291 for Alaska Airlines flights on this route.

  • Delta Flights From Seattle to Ontario

    Delta (7.9/10 from 8,008 reviews) operates around 12 flights from Seattle to Ontario in any given week. The average Delta airfare for this route is around $257, with deals from around $119 rare but found on momondo. Referenced prices are for round-trip Seattle to Ontario flight searches in the last 72 hours.

Why use momondo?

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

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Seattle to Ontario for you.

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

Yes. momondo allows you to filter the results for Seattle to Ontario flights to just show those with flexible booking policies.

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

momondo helps you find the best flight between Seattle and Ontario 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 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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