Latest deals
Insights
When to book
FAQs
Reviews
Price Alerts

Cheap flights from St. Louis to Los Angeles from $67

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 2/2. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

Discover deals from 900+ travel sites with momondo.

Save money when you book flights with momondo

Big names and deals

Big names and deals

Search 100s of travel sites to compare prices.

Filter for what you want

Filter for what you want

Free Wi-Fi? Stopover? Instantly customize your results.

Trusted and free

Trusted and free

We’re completely free to use - no hidden charges or fees.

Price Alerts

Price Alerts

Not ready to book? to track prices.
Search flight deals

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
9:32 pm - 12:10 pm
STL
-
ONT
16h 38m1 stop
Frontier Logo
7:17 pm - 9:26 pm
ONT
-
STL
24h 09m1 stop
$132Frontier
Sun, Feb 8 - Wed, Feb 18
Frontier Logo
4:51 pm - 9:34 pm
STL
-
ONT
6h 43m1 stop
Frontier Logo
6:00 am - 1:56 pm
ONT
-
STL
5h 56m1 stop
$136Frontier
Wed, Feb 25 - Sat, Feb 28
Frontier Logo
9:32 pm - 12:10 pm
STL
-
ONT
16h 38m1 stop
Frontier Logo
11:04 am - 9:06 pm
ONT
-
STL
8h 02m1 stop
$166Frontier
Sun, Feb 1 - Thu, Feb 5
Frontier Logo
3:46 pm - 11:24 pm
STL
-
ONT
9h 38m1 stop
Frontier Logo
1:05 pm - 8:50 pm
ONT
-
STL
5h 45m1 stop
$184Frontier
Sat, Jan 24 - Mon, Feb 2
Frontier Logo
4:51 pm - 1:11 pm
STL
-
ONT
22h 20m2 stops
Frontier Logo
6:00 am - 1:56 pm
ONT
-
STL
5h 56m1 stop
$187Frontier
Wed, Feb 25 - Sat, Feb 28
Frontier Logo
9:32 pm - 7:10 pm
STL
-
ONT
23h 38m1 stop
Frontier Logo
8:48 pm - 6:44 pm
ONT
-
STL
19h 56m2 stops
$189Frontier
Sun, Feb 1 - Thu, Feb 5
Frontier Logo
10:01 pm - 9:23 am
STL
-
ONT
13h 22m1 stop
Frontier Logo
11:04 am - 9:06 pm
ONT
-
STL
8h 02m1 stop
$200Frontier
Thu, Jan 29 - Thu, Feb 5
Frontier Logo
3:46 pm - 1:11 pm
STL
-
ONT
23h 25m2 stops
Frontier Logo
2:48 pm - 8:50 pm
ONT
-
STL
28h 02m1 stop
$201Frontier
Wed, Jan 21 - Sun, Jan 25
Frontier Logo
1:59 pm - 11:59 pm
STL
-
ONT
12h 00m1 stop
Frontier Logo
6:00 am - 1:56 pm
ONT
-
STL
5h 56m1 stop
$210Frontier
Fri, Feb 20 - Sat, Feb 28
Frontier Logo
10:11 pm - 1:11 pm
STL
-
ONT
17h 00m1 stop
Frontier Logo
3:24 pm - 11:19 am
ONT
-
STL
17h 55m1 stop
$211Frontier
Sun, Mar 1 - Thu, Mar 5

Alaska Airlines flights from St. Louis to Ontario

Our best Alaska Airlines deals on St. Louis to Ontario flight tickets
Alaska Airlines
Mar 3
STL7:00 amLambert-St Louis
10h 08m
1 stop
ONT3:08 pmOntario
Mar 10
ONT6:14 amOntario
29h 37m
1 stop
STL1:51 pmLambert-St Louis
$361
Find similar
Alaska Airlines
Feb 28
STL2:47 pmLambert-St Louis
10h 45m
1 stop
ONT11:32 pmOntario
Mar 10
ONT6:14 amOntario
29h 37m
1 stop
STL1:51 pmLambert-St Louis
$364
Find similar
Alaska Airlines
Feb 19
STL2:47 pmLambert-St Louis
10h 45m
1 stop
ONT11:32 pmOntario
Feb 24
ONT6:14 amOntario
29h 37m
1 stop
STL1:51 pmLambert-St Louis
$374
Find similar

Frontier flights from St. Louis to Ontario

Our best Frontier deals on St. Louis to Ontario flight tickets
Frontier
Feb 8
STL9:32 pmLambert-St Louis
16h 38m
1 stop
ONT12:10 pmOntario
Feb 18
ONT7:17 pmOntario
24h 09m
1 stop
STL9:26 pmLambert-St Louis
$132
Find similar
Frontier
Feb 25
STL4:51 pmLambert-St Louis
6h 43m
1 stop
ONT9:34 pmOntario
Feb 28
ONT6:00 amOntario
5h 56m
1 stop
STL1:56 pmLambert-St Louis
$136
Find similar
Frontier
Feb 1
STL9:32 pmLambert-St Louis
16h 38m
1 stop
ONT12:10 pmOntario
Feb 5
ONT11:04 amOntario
8h 02m
1 stop
STL9:06 pmLambert-St Louis
$166
Find similar

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 December 31, 2025.
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

Sun 2/8

9:32 pm-12:10 pm

1 stop16h 38m

Ontario

Wed 2/18

7:17 pm-9:26 pm

1 stop24h 09m

$132

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 2/25

4:51 pm-9:34 pm

1 stop6h 43m

Ontario

Sat 2/28

6:00 am-1:56 pm

1 stop5h 56m

$136

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sun 2/1

9:32 pm-12:10 pm

1 stop16h 38m

Ontario

Thu 2/5

11:04 am-9:06 pm

1 stop8h 02m

$166

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sat 1/24

3:46 pm-11:24 pm

1 stop9h 38m

Ontario

Mon 2/2

1:05 pm-8:50 pm

1 stop5h 45m

$184

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 2/25

4:51 pm-1:11 pm

2 stops22h 20m

Ontario

Sat 2/28

6:00 am-1:56 pm

1 stop5h 56m

$187

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sun 2/1

9:32 pm-7:10 pm

1 stop23h 38m

Ontario

Thu 2/5

8:48 pm-6:44 pm

2 stops19h 56m

$189

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Thu 1/29

10:01 pm-9:23 am

1 stop13h 22m

Ontario

Thu 2/5

11:04 am-9:06 pm

1 stop8h 02m

$200

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 1/21

3:46 pm-1:11 pm

2 stops23h 25m

Ontario

Sun 1/25

2:48 pm-8:50 pm

1 stop28h 02m

$201

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Fri 2/20

1:59 pm-11:59 pm

1 stop12h 00m

Ontario

Sat 2/28

6:00 am-1:56 pm

1 stop5h 56m

$210

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sun 3/1

10:11 pm-1:11 pm

1 stop17h 00m

Ontario

Thu 3/5

3:24 pm-11:19 am

1 stop17h 55m

$211

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
1
2

See travel insights to Los Angeles from

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 December 2025, prices for St. Louis to Ontario flights are approximately 85% 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
3,069 reviews
Search Frontier flights
DeltaPriceFrom $171Free CancellationRating
7.9
8,013 reviews
Search Delta flights
American AirlinesPriceFrom $264Free CancellationRating
7.2
11,074 reviews
Search American Airlines flights
SouthwestPriceFrom $292Free CancellationRating
8.0
4,251 reviews
Search Southwest flights
United AirlinesPriceFrom $292Free CancellationRating
7.4
9,124 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

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
Start using Trips
Find my bookings

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.
1 adult
Fri 1/30
Fri 2/6
By creating a price alert you accept our terms of use and privacy policy.

Find better results for your trip to the United States