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Cheap flights from St. Louis to Ontario from $54

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 Ontario departing on 1/8. 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 St. Louis to Los Angeles

Cheap round-trip flights

These are some of the best round-trip flight deals from St. Louis to Los Angeles that have been recently found on momondo from popular airlines, departing in the coming months.

Cheap one-way flights

Flying one-way? These are some of the best deals recently discovered on momondo for flights from St. Louis to Los Angeles.

Cheap last minute flights

Planning a quick getaway from St. Louis to Los Angeles? These are the last-minute flight deals available now.

Cheap direct flights

If you prefer a non-stop journey, check out our latest direct flight deals to Los Angeles, so you can enjoy a seamless trip without layovers.

Cheap bus & train deals from St. Louis to Los Angeles

Find recent round-trip train or bus tickets from St. Louis to Los Angeles.

All round-trip flight deals to Los Angeles

The cheapest plane tickets to Los Angeles found on KAYAK recently.
6:46 pm - 11:44 pmSTL-ONT
6h 58m1 stop
7:56 am - 7:31 pmONT-STL
9h 35m1 stop
$108Frontier
Find Deal
Wed, Jan 8 - Thu, Jan 16
11:08 pm - 7:26 amSTL-ONT
10h 18m1 stop
12:59 am - 9:16 amONT-STL
6h 17m1 stop
$124Frontier
Find Deal
Thu, Feb 27 - Tue, Mar 18
10:22 am - 10:32 pmSTL-ONT
14h 10m2 stops
7:05 am - 6:44 pmONT-STL
9h 39m1 stop
$315Delta
Find Deal
Tue, Jan 28 - Tue, Feb 4
5:00 pm - 11:53 pmSTL-ONT
8h 53m1 stop
6:00 am - 1:18 pmONT-STL
5h 18m1 stop
$316Delta
Find Deal
Tue, Jan 7 - Tue, Jan 14
11:38 am - 6:24 pmSTL-ONT
8h 46m2 stops
10:00 am - 7:30 pmONT-STL
7h 30m2 stops
$326American Airlines
Find Deal
Tue, Jan 28 - Tue, Feb 4
10:49 am - 10:04 pmSTL-ONT
13h 15m2 stops
10:50 pm - 10:58 amONT-STL
10h 08m1 stop
$332American Airlines
Find Deal
Wed, Feb 19 - Mon, Feb 24
6:10 am - 12:45 pmSTL-ONT
8h 35m1 stop
1:20 pm - 10:45 pmONT-STL
7h 25m1 stop
$407Southwest
Find Deal
Thu, Mar 13 - Thu, Mar 20
10:55 am - 10:45 pmSTL-ONT
13h 50m2 stops
5:05 am - 12:43 pmONT-STL
5h 38m1 stop
$413United Airlines
Find Deal
Wed, Mar 12 - Tue, Mar 18
4:36 pm - 8:51 pmSTL-ONT
6h 15m1 stop
10:47 am - 6:59 pmONT-STL
6h 12m1 stop
$428United Airlines
Find Deal
Thu, Jan 23 - Sun, Jan 26
9:45 am - 3:50 pmSTL-ONT
8h 05m2 stops
8:35 am - 7:40 pmONT-STL
9h 05m2 stops
$507Southwest
Find Deal
Thu, Mar 27 - Sun, Mar 30
6:46 pm - 11:44 pmSTL-ONT
6h 58m1 stop
$54Frontier
Find Deal
Wed, Jan 8
8:31 pm - 7:11 amSTL-ONT
12h 40m1 stop
$60Frontier
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Thu, Feb 6
6:59 pm - 12:09 amSTL-ONT
7h 10m1 stop
$69Frontier
Find Deal
Sat, Mar 8
4:36 pm - 9:57 pmSTL-ONT
7h 21m1 stop
$158United Airlines
Find Deal
Tue, Jan 7
2:49 pm - 10:39 pmSTL-ONT
9h 50m1 stop
$169Alaska Airlines
Find Deal
Mon, Feb 3
3:11 pm - 11:59 pmSTL-ONT
10h 48m2 stops
$181Alaska Airlines
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Tue, Apr 8
7:40 am - 12:19 pmSTL-ONT
6h 39m1 stop
$199Delta
Find Deal
Thu, Mar 13
4:36 pm - 8:51 pmSTL-ONT
6h 15m1 stop
$203United Airlines
Find Deal
Tue, Jan 21
5:00 pm - 10:52 pmSTL-ONT
7h 52m1 stop
$289Delta
Find Deal
Thu, Jan 9
11:36 am - 6:25 pmSTL-ONT
8h 49m2 stops
$428American Airlines
Find Deal
Thu, Jan 2
9:29 pm - 7:09 amSTL-ONT
11h 40m1 stop
7:05 pm - 8:29 pmONT-STL
23h 24m1 stop
$313Frontier
Find Deal
Mon, Dec 30 - Sun, Jan 5
9:29 pm - 7:09 amSTL-ONT
11h 40m1 stop
12:59 am - 8:13 amONT-STL
5h 14m1 stop
$358Frontier
Find Deal
Mon, Dec 30 - Sun, Jan 5
9:29 pm - 12:03 pmSTL-ONT
16h 34m1 stop
12:59 am - 9:19 pmONT-STL
18h 20m1 stop
$453Frontier
Find Deal
Mon, Dec 30 - Sat, Jan 4
7:00 am - 11:59 pmSTL-ONT
18h 59m1 stop
6:39 pm - 1:53 pmONT-STL
17h 14m2 stops
$922Alaska Airlines
Find Deal
Mon, Dec 30 - Mon, Jan 6
5:17 pm - 11:41 pmSTL-ONT
8h 24m1 stop
1:15 pm - 9:34 pmONT-STL
6h 19m1 stop
$926Delta
Find Deal
Sun, Dec 29 - Fri, Jan 3
1:45 pm - 6:33 pmSTL-ONT
6h 48m1 stop
10:02 am - 10:21 pmONT-STL
10h 19m2 stops
$931American Airlines
Find Deal
Fri, Dec 27 - Thu, Jan 2
1:44 pm - 5:26 pmSTL-ONT
5h 42m1 stop
5:05 am - 7:57 pmONT-STL
12h 52m2 stops
$935United Airlines
Find Deal
Mon, Dec 30 - Wed, Jan 1
5:21 am - 12:06 pmSTL-ONT
8h 45m2 stops
10:02 am - 10:21 pmONT-STL
10h 19m2 stops
$936American Airlines
Find Deal
Fri, Dec 27 - Thu, Jan 2
7:00 am - 11:59 pmSTL-ONT
18h 59m1 stop
8:32 pm - 1:53 pmONT-STL
15h 21m2 stops
$985Alaska Airlines
Find Deal
Sun, Dec 29 - Sun, Jan 5
4:43 pm - 8:49 pmSTL-ONT
6h 06m1 stop
1:57 pm - 12:48 pmONT-STL
20h 51m2 stops
$1,059United Airlines
Find Deal
Sun, Dec 29 - Fri, Jan 3

American Airlines flights from St. Louis to Ontario

Our best American Airlines deals on St. Louis to Ontario flight tickets
American Airlines
Jan 28
STL11:38 amLambert-St Louis
8h 46m
2 stops
ONT6:24 pmOntario
Feb 4
ONT10:00 amOntario
7h 30m
2 stops
STL7:30 pmLambert-St Louis
American Airlines
Feb 19
STL10:49 amLambert-St Louis
13h 15m
2 stops
ONT10:04 pmOntario
Feb 24
ONT10:50 pmOntario
10h 08m
1 stop
STL10:58 amLambert-St Louis
American Airlines
Jan 29
STL9:36 amLambert-St Louis
10h 48m
2 stops
ONT6:24 pmOntario
Feb 6
ONT10:00 amOntario
10h 09m
2 stops
STL10:09 pmLambert-St Louis

Frontier flights from St. Louis to Ontario

Our best Frontier deals on St. Louis to Ontario flight tickets
Frontier
Jan 8
STL6:46 pmLambert-St Louis
6h 58m
1 stop
ONT11:44 pmOntario
Jan 16
ONT7:56 amOntario
9h 35m
1 stop
STL7:31 pmLambert-St Louis
Frontier
Feb 27
STL11:08 pmLambert-St Louis
10h 18m
1 stop
ONT7:26 amOntario
Mar 18
ONT12:59 amOntario
6h 17m
1 stop
STL9:16 amLambert-St Louis
Frontier
Feb 8
STL7:09 pmLambert-St Louis
6h 38m
1 stop
ONT11:47 pmOntario
Feb 14
ONT2:43 pmOntario
5h 25m
1 stop
STL10:08 pmLambert-St Louis

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, April 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 $176. If you aren’t able to travel during the month of April, then book flights to Ontario from St. Louis during June instead. Flights to Ontario in June, while not as cheap as those in April, still average around $217.

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 Tuesday when prices can be found for as low as $291. This is often the case because there is less demand to fly during this day of the week. When flying out on a Sunday, the most expensive travel day of the week, you can expect to see flight prices from St. Louis to Ontario for around $376.

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

In the evening is the cheapest time of day to fly from St. Louis to Ontario when you can find flight prices for as low as $219. Flying to Ontario in the evening 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 $442 on average. Flights to Ontario from St. Louis in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

How far in advance should I book a flight to Ontario?

Most flyers found that booking tickets 16 days in advance of their planned departure date is the best time to get cheap flights to Ontario. During this timeframe, flight prices are around $338. However, in the past 72 hours, people saw flights from St. Louis for as low as $136.

Can stopping save me money on St. Louis to Ontario flights?

You could potentially save up to 70% on your flight if you consider stops on a St. Louis to Ontario flight.

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

As of December 2024, prices for St. Louis to Ontario flights are approximately 0% 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

Best Price Found

$54

Fastest flight time

5h 50m

Direct flights

None

Airports in Ontario

1 airport
The best one-way flight to Ontario from St. Louis in the past 72 hours is $54. The best round-trip flight deal from St. Louis to Ontario found on momondo in the last 72 hours is $108.
The fastest flight from St. Louis to Ontario takes 5h 50m
There are no direct flights from St. Louis to Ontario. Popular non-direct route for this connection is Lambert-St Louis Airport - Ontario Airport.
There is 1 airport near Ontario: Ontario (ONT)

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

    A flight from Lambert-St Louis to Ontario will travel around 1552.8 mi. 6h 05m 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 plane model from St. Louis to Ontario?

  • 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 $117Free CancellationRating
6.1
3,465 reviews
Search Frontier flights
American AirlinesPriceFrom $281Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
DeltaPriceFrom $286Free CancellationRating
8.0
8,580 reviews
Search Delta flights
United AirlinesPriceFrom $326Free CancellationRating
7.4
9,007 reviews
Search United Airlines flights
SouthwestPriceFrom $341Free CancellationRating
8.1
4,758 reviews
Search Southwest 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.


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