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Cheap flights from Seattle to Los Angeles from $79

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 9/24. 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

Frontier Logo
8:43 pm - 11:50 pmSEA-ONT
27h 07m1 stop
Frontier Logo
10:30 am - 1:26 pmONT-SEA
2h 56mnonstop
$107Frontier
Find Deal
Fri, Oct 24 - Mon, Oct 27
Frontier Logo
7:17 pm - 9:58 pmSEA-ONT
2h 41mnonstop
Frontier Logo
8:02 am - 10:55 amONT-SEA
2h 53mnonstop
$108Frontier
Find Deal
Fri, Nov 14 - Mon, Nov 17
Frontier Logo
1:18 pm - 11:50 pmSEA-ONT
10h 32m1 stop
Frontier Logo
8:02 am - 10:55 amONT-SEA
2h 53mnonstop
$112Frontier
Find Deal
Thu, Oct 30 - Mon, Nov 3
Frontier Logo
8:28 am - 11:08 amSEA-ONT
2h 40mnonstop
Frontier Logo
10:30 am - 1:26 pmONT-SEA
2h 56mnonstop
$113Frontier
Find Deal
Mon, Oct 13 - Mon, Oct 20
Frontier Logo
8:28 am - 11:08 amSEA-ONT
2h 40mnonstop
Frontier Logo
10:30 am - 1:26 pmONT-SEA
2h 56mnonstop
$114Frontier
Find Deal
Mon, Oct 13 - Mon, Oct 27
Frontier Logo
8:28 am - 11:08 amSEA-ONT
2h 40mnonstop
Frontier Logo
10:30 am - 1:26 pmONT-SEA
2h 56mnonstop
$115Frontier
Find Deal
Fri, Oct 24 - Mon, Oct 27
Frontier Logo
8:28 am - 11:08 amSEA-ONT
2h 40mnonstop
Frontier Logo
10:30 am - 1:26 pmONT-SEA
2h 56mnonstop
$116Frontier
Find Deal
Fri, Oct 24 - Mon, Oct 27
Frontier Logo
8:28 am - 11:08 amSEA-ONT
2h 40mnonstop
Frontier Logo
10:30 am - 1:26 pmONT-SEA
2h 56mnonstop
$117Frontier
Find Deal
Fri, Oct 24 - Sun, Oct 26
Multiple Airlines Logo
1:00 pm - 8:03 pmSEA-ONT
7h 03m1 stop
Multiple Airlines Logo
6:17 pm - 9:10 pmONT-SEA
2h 53mnonstop
$142Multiple Airlines
Find Deal
Thu, Dec 4 - Sun, Dec 7
Multiple Airlines Logo
8:28 am - 11:08 amSEA-ONT
2h 40mnonstop
Multiple Airlines Logo
1:31 pm - 4:14 pmONT-SEA
2h 43mnonstop
$153Multiple Airlines
Find Deal
Sun, Oct 12 - Sat, Oct 25

Frontier flights from Seattle to Ontario

Our best Frontier deals on Seattle to Ontario flight tickets
Frontier
Oct 24
SEA8:43 pmSeattle/Tacoma Intl
27h 07m
1 stop
ONT11:50 pmOntario
Oct 27
ONT10:30 amOntario
2h 56m
SEA1:26 pmSeattle/Tacoma Intl
$107
Find similar
Frontier
Nov 14
SEA7:17 pmSeattle/Tacoma Intl
2h 41m
ONT9:58 pmOntario
Nov 17
ONT8:02 amOntario
2h 53m
SEA10:55 amSeattle/Tacoma Intl
$108
Find similar
Frontier
Oct 30
SEA1:18 pmSeattle/Tacoma Intl
10h 32m
1 stop
ONT11:50 pmOntario
Nov 3
ONT8:02 amOntario
2h 53m
SEA10:55 amSeattle/Tacoma Intl
$112
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 September 16, 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

Fri 10/24

8:43 pm-11:50 pm

1 stop27h 07m

Ontario

Mon 10/27

10:30 am-1:26 pm

Nonstop2h 56m

$107

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 11/14

7:17 pm-9:58 pm

Nonstop2h 41m

Ontario

Mon 11/17

8:02 am-10:55 am

Nonstop2h 53m

$108

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 10/30

1:18 pm-11:50 pm

1 stop10h 32m

Ontario

Mon 11/3

8:02 am-10:55 am

Nonstop2h 53m

$112

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Mon 10/13

8:28 am-11:08 am

Nonstop2h 40m

Ontario

Mon 10/20

10:30 am-1:26 pm

Nonstop2h 56m

$113

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Mon 10/13

8:28 am-11:08 am

Nonstop2h 40m

Ontario

Mon 10/27

10:30 am-1:26 pm

Nonstop2h 56m

$114

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 10/24

8:28 am-11:08 am

Nonstop2h 40m

Ontario

Mon 10/27

10:30 am-1:26 pm

Nonstop2h 56m

$115

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 10/24

8:28 am-11:08 am

Nonstop2h 40m

Ontario

Mon 10/27

10:30 am-1:26 pm

Nonstop2h 56m

$116

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Fri 10/24

8:28 am-11:08 am

Nonstop2h 40m

Ontario

Sun 10/26

10:30 am-1:26 pm

Nonstop2h 56m

$117

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Thu 12/4

1:00 pm-8:03 pm

1 stop7h 03m

Ontario

Sun 12/7

6:17 pm-9:10 pm

Nonstop2h 53m

$142

SeattleOntario

SEA - ONT

SEAONT

Seattle/Tacoma Intl

Sun 10/12

8:28 am-11:08 am

Nonstop2h 40m

Ontario

Sat 10/25

1:31 pm-4:14 pm

Nonstop2h 43m

$153

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 $177. If you aren’t able to travel during the month of October, then book flights to Ontario from Seattle during September instead. Flights to Ontario in September, while not as cheap as those in October, still average around $187.

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 Thursday when prices can be found for as low as $196. This is often the case because there is less demand to fly during this day of the week. When flying out on a Monday, the most expensive travel day of the week, you can expect to see flight prices from Seattle to Ontario for around $226.

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 $182. 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 morning when prices are $229 on average. Flights to Ontario from Seattle in the morning 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 $215 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 $168 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 September 2025, prices for Seattle to Ontario flights are approximately 14% 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

$117

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 $117. The best round-trip flight deal from Seattle to Ontario found on momondo in the last 72 hours is $159.
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?

    The distance between Seattle/Tacoma Intl and Ontario is about 966.6 mi. A reasonable flight in good conditions will take 2h 36m.

  • 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 $69Free CancellationRating
5.8
3,174 reviews
Search Frontier flights
Hawaiian AirlinesPriceFrom $98Free CancellationRating
7.8
2,724 reviews
Search Hawaiian Airlines flights
DeltaPriceFrom $117Free CancellationRating
7.9
7,957 reviews
Search Delta flights
Alaska AirlinesPriceFrom $154Free CancellationRating
8.0
10,000 reviews
Search Alaska Airlines flights
SouthwestPriceFrom $156Free CancellationRating
8.0
4,242 reviews
Search Southwest flights

  • Alaska Airlines Flights From Seattle to Ontario

    Alaska Airlines flies from Seattle to Ontario around 15 times per week, with 10,000 momondo users rating the airline 8.0/10. The cheapest Alaska Airlines deal from Seattle to Ontario in the last 72 hours was $154 (round-trip), much lower than the average airfare cost of $278 for Alaska Airlines flights on this route.

  • Delta Flights From Seattle to Ontario

    Delta (7.9/10 from 7,957 reviews) operates around 13 flights from Seattle to Ontario in any given week. The average Delta airfare for this route is around $257, with deals from around $117 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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