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Cheap flights from St. Louis to Los Angeles from $62

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Los Angeles departing on 2/14. 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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0 bags

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Find the cheapest flights from St. Louis to Los Angeles

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
3:46 pm - 11:24 pm
STL
-
ONT
9h 38m1 stop
Frontier Logo
8:36 am - 1:58 pm
ONT
-
STL
27h 22m1 stop
$133Frontier
sáb., feb. 7 - mar., feb. 10
Frontier Logo
7:39 pm - 12:20 am
STL
-
ONT
6h 41m1 stop
Frontier Logo
6:20 am - 12:50 pm
ONT
-
STL
28h 30m1 stop
$134Frontier
vie., feb. 6 - dom., feb. 8
Frontier Logo
9:32 pm - 12:10 pm
STL
-
ONT
16h 38m1 stop
Frontier Logo
8:36 am - 1:58 pm
ONT
-
STL
27h 22m1 stop
$135Frontier
dom., feb. 8 - mar., feb. 10
Frontier Logo
3:46 pm - 11:24 pm
STL
-
ONT
9h 38m1 stop
Frontier Logo
6:20 am - 12:50 pm
ONT
-
STL
28h 30m1 stop
$142Frontier
sáb., ene. 24 - dom., ene. 25
Frontier Logo
1:40 pm - 12:20 am
STL
-
ONT
12h 40m1 stop
Frontier Logo
7:15 am - 2:46 pm
ONT
-
STL
5h 31m1 stop
$144Frontier
lun., ene. 26 - mié., ene. 28
Frontier Logo
9:45 pm - 1:37 pm
STL
-
ONT
17h 52m1 stop
Frontier Logo
8:36 am - 1:58 pm
ONT
-
STL
27h 22m1 stop
$145Frontier
lun., feb. 2 - mar., feb. 10
Frontier Logo
10:01 pm - 9:23 am
STL
-
ONT
13h 22m1 stop
Frontier Logo
6:20 am - 12:50 pm
ONT
-
STL
28h 30m1 stop
$146Frontier
jue., feb. 5 - dom., feb. 8
Frontier Logo
3:46 pm - 11:24 pm
STL
-
ONT
9h 38m1 stop
Frontier Logo
7:15 am - 2:46 pm
ONT
-
STL
5h 31m1 stop
$148Frontier
sáb., ene. 31 - sáb., feb. 7
Frontier Logo
8:12 pm - 11:59 pm
STL
-
ONT
5h 47m1 stop
Frontier Logo
10:03 pm - 12:15 pm
ONT
-
STL
12h 12m1 stop
$150Frontier
mié., mar. 11 - mié., mar. 18
Frontier Logo
7:39 pm - 12:20 am
STL
-
ONT
6h 41m1 stop
Frontier Logo
7:17 pm - 9:26 pm
ONT
-
STL
24h 09m1 stop
$151Frontier
vie., feb. 6 - mié., feb. 11

Frontier flights from St. Louis to Ontario

Our best Frontier deals on St. Louis to Ontario flight tickets
Frontier
Feb 7
STL3:46 pmLambert-St Louis
9h 38m
1 stop
ONT11:24 pmOntario
Feb 8
ONT6:20 amOntario
28h 30m
1 stop
STL12:50 pmLambert-St Louis
$133
Frontier
Feb 6
STL7:39 pmLambert-St Louis
6h 41m
1 stop
ONT12:20 amOntario
Feb 10
ONT8:36 amOntario
27h 22m
1 stop
STL1:58 pmLambert-St Louis
$134
Frontier
Feb 8
STL9:32 pmLambert-St Louis
16h 38m
1 stop
ONT12:10 pmOntario
Feb 10
ONT8:36 amOntario
27h 22m
1 stop
STL1:58 pmLambert-St Louis
$135

United Airlines flights from St. Louis to Ontario

Our best United Airlines deals on St. Louis to Ontario flight tickets
United Airlines
Jan 22
STL8:45 amLambert-St Louis
6h 02m
1 stop
ONT12:47 pmOntario
Jan 27
ONT5:05 amOntario
10h 38m
2 stops
STL5:43 pmLambert-St Louis
$486
United Airlines
Jan 22
STL11:20 amLambert-St Louis
11h 38m
2 stops
ONT8:58 pmOntario
Jan 27
ONT5:05 amOntario
8h 58m
2 stops
STL4:03 pmLambert-St Louis
$492
United Airlines
Jan 22
STL8:45 amLambert-St Louis
10h 58m
2 stops
ONT5:43 pmOntario
Jan 25
ONT1:24 pmOntario
5h 34m
1 stop
STL8:58 pmLambert-St Louis
$562

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis 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 enero 8, 2026.
Use the filters below to find and compare flights from St. Louis to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

sáb. 2/7

3:46 pm-11:24 pm

1 stop9h 38m

Ontario

mar. 2/10

8:36 am-1:58 pm

1 stop27h 22m

$133

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

vie. 2/6

7:39 pm-12:20 am

1 stop6h 41m

Ontario

dom. 2/8

6:20 am-12:50 pm

1 stop28h 30m

$134

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

dom. 2/8

9:32 pm-12:10 pm

1 stop16h 38m

Ontario

mar. 2/10

8:36 am-1:58 pm

1 stop27h 22m

$135

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

sáb. 1/24

3:46 pm-11:24 pm

1 stop9h 38m

Ontario

dom. 1/25

6:20 am-12:50 pm

1 stop28h 30m

$142

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

lun. 1/26

1:40 pm-12:20 am

1 stop12h 40m

Ontario

mié. 1/28

7:15 am-2:46 pm

1 stop5h 31m

$144

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

lun. 2/2

9:45 pm-1:37 pm

1 stop17h 52m

Ontario

mar. 2/10

8:36 am-1:58 pm

1 stop27h 22m

$145

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

jue. 2/5

10:01 pm-9:23 am

1 stop13h 22m

Ontario

dom. 2/8

6:20 am-12:50 pm

1 stop28h 30m

$146

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

sáb. 1/31

3:46 pm-11:24 pm

1 stop9h 38m

Ontario

sáb. 2/7

7:15 am-2:46 pm

1 stop5h 31m

$148

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

mié. 3/11

8:12 pm-11:59 pm

1 stop5h 47m

Ontario

mié. 3/18

10:03 pm-12:15 pm

1 stop12h 12m

$150

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

vie. 2/6

7:39 pm-12:20 am

1 stop6h 41m

Ontario

mié. 2/11

7:17 pm-9:26 pm

1 stop24h 09m

$151

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 St. Louis 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, November is the cheapest month to fly from St. Louis to Ontario. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $292. If you aren’t able to travel during the month of November, then book flights to Ontario from St. Louis during August instead. Flights to Ontario in August, while not as cheap as those in November, still average around $301.

How have St. Louis to Ontario flight prices changed over time?

As of January 2026, prices for St. Louis to Ontario flights are approximately 141% more expensive when compared to flights at the same time last year.

When to book flights from St. Louis to Ontario

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

Cheap St. Louis to Ontario (STL to ONT) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Ontario

Fastest flight time

5h 48m

Direct flights

None
The fastest flight from St. Louis to Ontario takes 5h 48m
There are no direct flights from St. Louis to Ontario. There are no popular flight routes from St. Louis to Ontario.
Search flight deals

  • How far is Lambert-St Louis to Ontario by plane?

    A flight from Lambert-St Louis to Ontario will travel around 1552.8 mi. 5h 48m is a normal flight duration for this route.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Ontario Airport?

    Prices for flights from Lambert-St Louis Airport to Ontario Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Ontario Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to Ontario 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 Lambert-St Louis Airport to Ontario Airport.

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

    The required travel and health documents for your Ontario Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Ontario Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

  • What is the most popular airline from St. Louis to Ontario?

Best airlines flying from St. Louis to Ontario

Compare and see reviews for airlines that fly from St. Louis to Ontario with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $137Free CancellationRating
5.7
3,062 reviews
Search Frontier flights
DeltaPriceFrom $171Free CancellationRating
7.9
8,025 reviews
Search Delta flights
American AirlinesPriceFrom $264Free CancellationRating
7.2
11,095 reviews
Search American Airlines flights
SouthwestPriceFrom $292Free CancellationRating
8.0
4,250 reviews
Search Southwest flights
United AirlinesPriceFrom $292Free CancellationRating
7.4
9,139 reviews
Search United Airlines flights

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Ontario?

Finding the right flight to Ontario from St. Louis is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to Ontario quick and easy, saving you time and money.

Can I find flights from St. Louis to Ontario with flexible booking policies on momondo?

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

How can momondo help me find flights from St. Louis to Ontario?

momondo helps you find the best flight between St. Louis 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 St. Louis to Ontario right now. Can momondo alert me if prices change?

If you are simply researching potential flights to Ontario, momondo offers a useful price alert feature which will track prices for flights to Ontario from St. Louis and alert you when they change.

An easier way to manage your Ontario trip

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