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STL - ONT

Find cheap flights from St. Louis to Ontario from $55

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from St. Louis to Ontario departing on 5/2. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
0 bags
Sun 4/28
Sun 5/5

Search hundreds of travel sites at once for deals on flights to Ontario

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Ontario, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Ontario, as well as popular online travel agencies
In the last 7 days travelers have searched 46,342,885 times on KAYAK, and here is why:

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Cheap flight deals from St. Louis to Ontario

Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis to Ontario that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices and deals for you by selecting your travel dates.
Choose your dates
8:04 pm - 11:59 pmSTL-ONT
5h 55m1 stop
12:59 am - 9:25 amONT-STL
6h 26m1 stop
$76Frontier
Find Deal
Wed, May 15 - Fri, May 17
8:04 pm - 11:59 pmSTL-ONT
5h 55m1 stop
12:55 am - 9:47 amONT-STL
6h 52m1 stop
$89Frontier
Find Deal
Sat, Apr 20 - Fri, Apr 26
8:04 pm - 6:26 amSTL-ONT
12h 22m1 stop
10:49 pm - 10:18 amONT-STL
9h 29m1 stop
$90Frontier
Find Deal
Wed, Apr 24 - Wed, May 1
6:05 pm - 7:39 amSTL-ONT
15h 34m2 stops
10:42 pm - 10:46 amONT-STL
10h 04m1 stop
Fri, May 24 - Tue, May 28
7:00 am - 10:09 pmSTL-ONT
17h 09m2 stops
12:59 am - 2:29 pmONT-STL
11h 30m1 stop
Sun, Apr 21 - Sat, Apr 27
2:37 pm - 6:49 pmSTL-ONT
6h 12m1 stop
10:00 am - 5:16 pmONT-STL
5h 16m1 stop
$358American Airlines
Find Deal
Sat, Apr 20 - Sat, Apr 27
10:20 am - 9:37 pmSTL-ONT
13h 17m2 stops
6:00 am - 2:46 pmONT-STL
6h 46m1 stop
$493Delta
Find Deal
Sat, Apr 20 - Sat, Apr 27
11:40 am - 6:51 pmSTL-ONT
9h 11m2 stops
11:59 pm - 9:03 amONT-STL
7h 04m1 stop
$512American Airlines
Find Deal
Sat, May 25 - Sun, Jun 9
1:37 pm - 11:04 pmSTL-ONT
11h 27m2 stops
5:15 am - 4:29 pmONT-STL
9h 14m1 stop
$551United Airlines
Find Deal
Wed, Apr 17 - Sun, Apr 28
6:19 am - 11:04 pmSTL-ONT
18h 45m3 stops
5:15 am - 9:15 pmONT-STL
14h 00m2 stops
$586United Airlines
Find Deal
Wed, Apr 24 - Wed, May 1

Flights from St. Louis to Ontario - Travel Insights & Trends

Get data-powered insights and trends into flights from St. Louis to Ontario to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from St. Louis to Ontario?

The average price of all flights from St. Louis to Ontario clicked on KAYAK for each day over the last 12 months.
When flying from St. Louis to Ontario, you should consider leaving on a Thursday and avoid Fridays if you are looking for the best rates. For your return to St. Louis, you’ll find the best rates on Saturdays and the most expensive ones on Mondays.

What is the cheapest month to fly from St. Louis to Ontario?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for flights from St. Louis to Ontario, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.
The cheapest month for flights from St. Louis to Ontario is August, where tickets cost $199 on average. On the other hand, the most expensive months are June and April, where the average cost of tickets is $555 and $464 respectively.

How far in advance should I book a flight from St. Louis to Ontario?

To calculate daily average prices, KAYAK takes all prices for each day before departure over the last year for flights from St. Louis to Ontario, removes the top 0.1% to account for outliers, and then takes the average of all the values for each month.
To get a below average price on the flight from St. Louis to Ontario, you should book around 1 day before departure. For the absolute cheapest price, our data suggests you should book 37 days before departure.

Which airlines provide the cheapest flights from St. Louis to Ontario?

The cheapest price for the route for each airline clicked by KAYAK users in the last 72 hours.
In the last 72 hours, the cheapest one-way ticket from St. Louis to Ontario found on KAYAK was with Frontier for $55. Frontier proposed a round-trip connection from $76 and American Airlines from $358.

How long does a flight from St. Louis to Ontario take?

Flying between Ontario and St. Louis will take minimum 5h 55m and will require at least one stop.

Good to know

Low season

August

High season

September

Cheapest flight

$55
Best time to beat the crowds with an average 46% drop in price.
Most popular time to fly and prices are also 27% lower on average.
Flight from St. Louis to Ontario

When to book flights from St. Louis to Ontario

Are your dates flexible? Find out the best times to travel from St. Louis to Ontario based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from St. Louis to Ontario

  • What is the cheapest flight from St. Louis to Ontario?

    In the last 3 days, the lowest price for a flight from St. Louis to Ontario was $55 for a one-way ticket and $76 for a round-trip.

  • Do I need a passport to fly between St. Louis and Ontario?

    No

  • Which airports will I be using when flying from St. Louis to Ontario?

    St. Louis and Ontario are both served by 1 main airport. You will leave St. Louis from Lambert-St Louis and will be arriving at Ontario.

  • Which aircraft models fly most regularly from St. Louis to Ontario?

    The Airbus A320neo is the aircraft model that flies most regularly on the St. Louis to Ontario flight route.

  • Which airline alliances offer flights from St. Louis to Ontario?

    oneworld, Star Alliance, and SkyTeam are the airline alliances operating flights between St. Louis and Ontario, with oneworld being the most commonly used for this route.

  • Which is the best airline for flights from St. Louis to Ontario, Delta or United Airlines?

    The two airlines most popular with KAYAK users for flights from St. Louis to Ontario are Delta and United Airlines. With an average price for the route of $444 and an overall rating of 8.0, Delta is the most popular choice. United Airlines is also a great choice for the route, with an average price of $622 and an overall rating of 7.4.

  • How does KAYAK find such low prices on flights from St. Louis to Ontario?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from St. Louis to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from St. Louis to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from St. Louis is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from St. Louis to Ontario?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Ontario with an airline and back to St. Louis with another airline. Booking your flights between St. Louis and ONT can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from St. Louis to Ontario?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Ontario from St. Louis up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

See more FAQs

Top 4 airlines serving from St. Louis to Ontario

Need help choosing which airline to fly with from St. Louis to Ontario? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to KAYAK reviews.
8.0
DeltaOverall score based on 11402 reviews
86crew
81overall
79comfort
80entertainment
82boarding
75food
Airline reviews

I didn’t like that I could not select my seat and was assigned a seat when I checked in at LAX

Read more about Delta

I didn’t like that I could not select my seat and was assigned a seat when I checked in at LAX

Great experience overall. Check in at Austin was congested as they only have about 6 check in kiosks, one was broken, and there was a lot of Spring Break travelers.

Bag drop off was slow and annoying. Only 2 agents at the entire delta desk, and no one directing traffic for what line to be in, many confused people slowed down the process. Boarding was fine. Seats in Delta comfort plus were fine. Snacks were great! Definitely a bonus. The entertainment system was awful — old, slow, not responsive, and completely unable to play games due to some kind of error. But on the other hand, thank you to Delta for the free WiFi. That made it better.

Everything was very good other than I had selected a specific seat when I booked the flight and they changed it once I checked-in the day before my flight. I was still in first class but lost my aisle seat for a window seat. Being tall, the aisle offers more comfort so I always select an aisle seat.

Flight diverted in SD. Later take off in Seattle by 1.3hrs

Crew was not friendly when I went to request a seat change.

Really impressive staff at airport and on plane, especially given how busy it was

The plane smelled like a sewer. Multiple passengers complained. It’s a safety and quality issue to clean these planes.

Was a great smooth flight from Detroit to San Diego.

The boarding process was terrible especially with an indirect flight Chicago to Seattle to San Diego was terrible talking about we overbooked a flight idk if I’d take this airline ever again we got off our flight from Chicago to Seattle and we traveled for business and they told us our connecting flight was over booked and their was no seats asking people to take a delayed next flight and they don’t tell anyone coughing to wear masks seats 30A-B were terrible during the flight no one wants to sit next to people coughing all around I don’t want to be sick traveling for work or get sick anytime it’s very upsetting the staff doesn’t take this stuff serious to tell them to wear masks when they see people coughing and sneezing

For a 22 minute flight all you expect is for it to be safe and comfortable

I was not able to buy food in the flight. They refer to include your Credit card in the APP, and if you are not from USA (i have a credit card form Canada) it is not possible

Over two hours wait to get wheelchair assistance from arrival to the departure gate for LA was unreasonable even though there appreared to be heavy demand.

Airline did not explain reasons why flight was delayed two hours. Explanations were badly needed and rarely provided. Problem seemed to clearly be the airline’s fault and not the fault of the weather or airport.

I was delighted that we were able to get on the 4:40 pm flight rather than our original booking at 6:55 pm!! Other than that, the flight was comfortable and landed early😊

The flight and crew were fine. The entertainment- the sound was so bad through the headphones I could barely understand it and it was a show I had seen before. The food might have been fine but having to have an account with united in order to access the app in order to pay for the food was rage inducing. I had entered my credit card info at home and logged in as guest but that wouldn’t allow the “wallet” tab to open in the app. And then the wifi was so bad that it took about 45 minutes to fully log in and get all the info working at which time I missed the food. You shouldn’t have to give your address, email and phone number in order to get a hamburger.

The control panel for the seat back screen did not work at all after takeoff.

United airline kept delaying our flight back to Phoenix for 8 hours before they cancelled it! If they know that we are not flying out for whatever the reason is, why did they keep lying to us for hours. We could find another flight earlier or even find a hotel with a shuttle. But cancellation at about midnight was not fun. We stayed in the airport all night till the following morning when we bought an Alaska tickets to go back to Phoenix. Total of 14 hours in the airport.

Poor seating comfort, seat cushion too thin, very uncomfortable. My luggage didi not make the flight due to equipment change. At least. United had it delivered the next day. I was without my toilet items for one day.

The crew was nice but the people going to Orange County are so entitled. Everyone thinks everything is suppose for be perfect for them. Tough crowd.

Plane was good but was delayed. probably not AA fault but caused a 1 hour delay. Seating was cramped.

5 hour flight - full flight - not enough room to use my computer - slightly delayed - Admirals club was excellent quality food, drink made up for flight seating. No food offerred on flight, you ahd to prebook.

We experience delays on departure and connecting flights resulting in 14 hour to our next departure. We were accommodated with a night's stay but was only provided a 12 dollar meals accommodation. The airlines rules state.at least 50 dollars. In any case, it can not make up for the whole day missed on our vacation in Sydney Australia.

I can say I will not be taking this airline again any time soon. Seat were uncomfortable and too tight. Lack of chair screen and little overhead space.

Plane felt so crowded and tightly packed. The chair itself was not comfortable.

They attended to my needs as I couldn't walk and they provided a wheelchair for me.q

Poor availability of food. Cold cabin temperature. Extremely long waiting time for a flight attendant to respond to a call button signal.

2.5h delay due to unruly passenger in first class. Had to be removed from the flight. No food unless pre ordered. Didn't know we would need it because of delay.

This time my flight was smooth and uneventful. They started boarding even earlier than it was scheduled. I was pleasantly surprised. Thank you!

Only my carry that was taken and found it in my final destination

It was impossible to change a carry-on for a checked bag after the initial selection. The flight was delayed 14 hours "to allow for a late arriving aircraft." The seats were shockingly uncomfortable. This was only the second time I've seen seats that didn't recline in an airline. The first was in an East Bloc airline before the fall if the Iron Curtain.

The boarding time. I was in Section 1 the lady in charge just let people in section 3 without see us. Make a line , I have to step out and ask her. We were in the line and she just take my ticket and that’s it, so if I don’t ask her she could leave us at the end! We paid more for that privilege and. She doesn’t care….

Was just ok with over selling I guess. A lot of people in a short space and when we finally arrive i20 minutes, waiting to get out from the plain because we were waiting authorization for out boarding? Something like that.

See my previous comment which is mostly about our flight from Phoenix to SFO

The check in at the airport was awful. Told I need to pay for a bag. The item was taken at screening. I went back to get my $ back and they gave me a coupon with a QR code that doesn’t work. Worst costumer service ever!!!!!

4 hour delay because they used our aircraft to fly a different segment (per the captain)

Lost baggage on my connecting flight. 24 hours later, still no update on my bags.

I have come to accept Frontier as an absolute no-frills airline, paying for everything I want. A 4.5-hour flight should provide me with a complimentary beverage—rather, $4.9x for a soda. Or a bottle of water ought to be extended at no cost. 4 beers are on the menu, but only 1 type of beer is available (at $9.95). Also, so many restrictions to using a voucher from Barclay‘s Credit Card. Finally, try to reach a live agent for Frontier- impossible!

I had to cancel within 1hour of the reservation an they put you through hell to . no live customer service desk. I'm handy caped and they make it almost impossible to cancel. They are steeling my money. You should not have that airline on your site. Contact me and I will give you all info. Of what the are doing to me just notable treatment they are set up like that to take people

absolutely horrific. delayed flights, overbooking. over charging. nightmare service beyond words. stay away.

Book cheap flights from St. Louis to Ontario

Recent one-way flight deals

 
Only flying one-way? Below are some of the best one-way flight deals from St. Louis to Ontario found on KAYAK in the last 72 hours.
5/2Thu
1 stopFrontier
20h 48mSTL-ONT
$55
4/26Fri
1 stopFrontier
8h 20mSTL-ONT
$78
4/26Fri
3 stops
22h 04mSTL-ONT
$181
4/27Sat
2 stopsAmerican Airlines
8h 50mSTL-ONT
$228
4/27Sat
2 stopsUnited Airlines
16h 17mSTL-ONT
$244
4/3Wed
3 stops
36h 52mSTL-ONT
$253
5/2Thu
2 stopsAlaska Airlines
15h 44mSTL-ONT
$298
4/26Fri
2 stopsAlaska Airlines
12h 27mSTL-ONT
$309
4/19Fri
2 stopsUnited Airlines
11h 27mSTL-ONT
$339
7/2Tue
2 stopsAmerican Airlines
7h 42mSTL-ONT
$387

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Last minute flights from St. Louis to Ontario

Last minute flight, train and bus deals

 
These last-minute flight deals are the cheapest flights found on KAYAK in the last 72 hours for flights from St. Louis to Ontario that are departing in the next 10 days.
4/1Mon
multi-stopFrontier
11h 52mSTL-ONT
4/4Thu
multi-stopFrontier
10h 58mONT-STL
$241
4/2Tue
multi-stopFrontier
10h 33mSTL-ONT
4/5Fri
multi-stopFrontier
9h 38mONT-STL
$242
4/2Tue
multi-stopFrontier
10h 33mSTL-ONT
4/9Tue
multi-stopFrontier
10h 10mONT-STL
$247
4/2Tue
multi-stopFrontier
14h 33mSTL-ONT
4/8Mon
multi-stopFrontier
18h 15mONT-STL
$251
4/1Mon
multi-stopFrontier
11h 52mSTL-ONT
4/5Fri
multi-stopFrontier
9h 38mONT-STL
$282
4/1Mon
multi-stopFrontier
27h 41mSTL-ONT
4/3Wed
multi-stopFrontier
14h 46mONT-STL
$285
3/30Sat
multi-stopFrontier
13h 33mSTL-ONT
4/1Mon
multi-stopFrontier
10h 28mONT-STL
$316
4/1Mon
multi-stopFrontier
27h 41mSTL-ONT
4/3Wed
multi-stopFrontier
14h 46mONT-STL
$328
3/30Sat
multi-stopFrontier
13h 33mSTL-ONT
3/31Sun
multi-stopFrontier
7h 13mONT-STL
$357
3/30Sat
multi-stopAlaska Airlines
10h 17mSTL-ONT
4/1Mon
multi-stopAlaska Airlines
9h 59mONT-STL
$1,758

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St. Louis - Ontario Flights

Departure:

St. Louis (STL)United States

Destination:

Ontario (ONT)United States

Return flight deals:

Ontario - St. Louis

Cabin classes:

$125