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$53+ Cheap flights from St. Louis to Ontario (STL - ONT)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 1/29. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ONT
Dec 7 — Dec 141
Sat 12/7
Sat 12/14
1 adult, Economy
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The best prices from Lambert-St Louis to Ontario are usually found in April or June, booked 16 days in advance, depart on a Tuesday or Monday and return on a Monday

Cheap flight deals from St. Louis to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Ontario (ONT). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated December 2, 2024.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Popular in

March

Cheapest in

April

Round-trip from

$108
(Frontier)

One-way from

$53
(Cheapflightsfares)
Provider with most accurate pricing for Lambert-St Louis-Ontario flight deals.
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Provider most trusted by Cheapflights users for Lambert-St Louis-Ontario flights.
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High demand for flights, 21% potential price rise
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Best time to find cheap flights, 48% potential price drop
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From Lambert-St Louis to Ontario
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One-way flight from Lambert-St Louis to Ontario
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Find flight deals from St. Louis to Ontario

Cheapest flights from St. Louis to Ontario
Explore the most affordable flight options available from St. Louis to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 2, 2024.

This Frontier deal was found by Cheapflights users on 12/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/158:34 pmSTL - ONT
1 stop12h 40mFrontier
Tue 12/1712:22 pmONT - STL
1 stop6h 24mFrontier
Deal found 12/1$148
This Delta deal was found by Cheapflights users on 12/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/187:20 amSTL - ONT
1 stop7h 05mDelta
Sat 1/116:00 amONT - STL
1 stop5h 18mDelta
Deal found 12/1$421
This United Airlines deal was found by Cheapflights users on 12/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/314:43 pmSTL - ONT
1 stop6h 06mUnited Airlines
Wed 1/15:05 amONT - STL
1 stop5h 43mUnited Airlines
Deal found 12/1$491
This American Airlines deal was found by Cheapflights users on 12/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/151:36 pmSTL - ONT
2 stops10h 27mAmerican Airlines
Tue 12/1712:53 pmONT - STL
1 stop7h 40mAmerican Airlines
Deal found 12/1$521
This Trip.com deal was found by Cheapflights users on 12/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/25:38 pmSTL - ONT
1 stop8h 26mMultiple Airlines
Mon 12/911:46 amONT - STL
2 stops25h 35mMultiple Airlines
Deal found 12/1$723
This Alaska Airlines deal was found by Cheapflights users on 12/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/107:00 amSTL - ONT
1 stop7h 58mAlaska Airlines
Sun 12/157:00 amONT - STL
2 stops14h 59mAlaska Airlines
Deal found 12/1$725

Find flights from St. Louis to Ontario within your budget

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, Cheapflights users made 2,650,959 searches. Data last updated December 2, 2024.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sat 2/22

6:53 pm-12:09 am

1 stop7h 16m

Ontario

Sun 2/23

12:59 am-9:16 am

1 stop6h 17m

$108

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Tue 1/28

2:49 pm-10:38 am

1 stop21h 49m

Ontario

Tue 2/4

6:00 am-1:53 pm

1 stop29h 53m

$302

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sat 2/1

5:00 pm-10:52 pm

1 stop7h 52m

Ontario

Tue 2/4

7:05 am-6:44 pm

1 stop9h 39m

$326

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Thu 2/13

11:25 am-11:58 pm

2 stops14h 33m

Ontario

Mon 2/17

2:43 pm-10:08 pm

1 stop5h 25m

$331

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Thu 1/30

2:15 pm-9:58 pm

2 stops9h 43m

Ontario

Tue 2/4

6:10 am-4:23 pm

2 stops8h 13m

$356

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Tue 2/11

8:27 am-12:41 pm

1 stop6h 14m

Ontario

Tue 2/18

6:00 am-3:11 pm

1 stop7h 11m

$416

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 1/29

7:09 pm-11:47 pm

1 stop6h 38m

$53

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Tue 2/25

7:00 am-4:59 pm

2 stops11h 59m

$147

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 1/1

7:04 am-11:46 am

1 stop6h 42m

$163

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Thu 1/30

6:00 am-3:25 pm

2 stops11h 25m

$172

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/1

Showing 1-10 of 13 results
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Compare providers for flights from St. Louis to Ontario

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Ontario in December.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
PricelinePrice Accuracy1 starTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on St. Louis-Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Ontario flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from St. Louis to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from St. Louis with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Travel insights for flights from St. Louis to Ontario

Get recent, data-driven insights about flights from St. Louis to Ontario including ideal travel times, pricing trends, and more.

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

Use this chart to determine the optimal time to book a round-trip flight from St. Louis to Ontario. Price data was last updated on November 22, 2024.

The price you pay for your flight from St. Louis to Ontario may vary depending on when you book. For the best chance of a lower fare, look to book 16 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from St. Louis to Ontario?

Currently, September is the cheapest month in which you can book a flight from St. Louis to Ontario (average of $236). Flying from St. Louis to Ontario in December is currently the most expensive (average of $298). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from STL to ONT?

Find hourly flight availability from St. Louis to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated December 2, 2024.

It’s optimal to fly from St. Louis to Ontario in the evening. By choosing this option you can save up to 50% on the cost of your flight, compared to a flight in the morning.

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

Use this chart to determine the cheapest time to fly round-trip from St. Louis to Ontario. Price data was last updated on November 24, 2024.

Travelers seeking maximum savings on their St. Louis to Ontario flight should consider departing on Wednesday evenings when fares are most often at their lowest. Monday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Ontario. Reviews last updated December 2, 2024.
Peruse reviews from past customers who have flown with Frontier, Alaska Airlines and United Airlines from St. Louis to Ontario to help guide your decision. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,951 reviews

Comfort

8.1

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.2

Reviews

1 / 10

Flight was delayed by one hour and 40 minutes. Also baggage was delivered late at Boston. This delay made me miss my connection from Boston to Hyderabad

Southwest
8.1
Very good
4,951 reviews
Southwest
8.1
Very good
4,951 reviews

Comfort

8.1

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.2

Reviews

1 / 10

Flight was delayed by one hour and 40 minutes. Also baggage was delivered late at Boston. This delay made me miss my connection from Boston to Hyderabad

Alaska Airlines
8.0
Very good
9,513 reviews
Southwest
8.1
Very good
4,951 reviews

Comfort

8.1

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.2

Reviews

1 / 10

Flight was delayed by one hour and 40 minutes. Also baggage was delivered late at Boston. This delay made me miss my connection from Boston to Hyderabad

Delta
8.0
Very good
8,698 reviews
Southwest
8.1
Very good
4,951 reviews

Comfort

8.1

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.2

Reviews

1 / 10

Flight was delayed by one hour and 40 minutes. Also baggage was delivered late at Boston. This delay made me miss my connection from Boston to Hyderabad

United Airlines
7.4
Good
9,141 reviews
Southwest
8.1
Very good
4,951 reviews

Comfort

8.1

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.2

Reviews

1 / 10

Flight was delayed by one hour and 40 minutes. Also baggage was delivered late at Boston. This delay made me miss my connection from Boston to Hyderabad

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
4,951 reviews

Comfort

8.1

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.2

Reviews

1 / 10

Flight was delayed by one hour and 40 minutes. Also baggage was delivered late at Boston. This delay made me miss my connection from Boston to Hyderabad

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What are the cheapest airlines flying from St. Louis to Ontario round-trip?

    Frontier, at $108, was found to be the cheapest airline from St. Louis to Ontario.Alternate airlines to your destination round-trip include Alaska Airlines and Delta. Frontier is priced at 68% lower than the current average price of a flight leaving 3 months from now.

  • What are the cheapest airlines to fly from St. Louis to Ontario one-way?

    The cheapest airline one-way is Frontier, with whom users have recently found tickets for as low as $53. However, be on the lookout for offers from Alaska Airlines and American Airlines, as they are both options that can get you from St. Louis to Ontario for a low price.

  • Can I find deals for flights from St. Louis to Ontario that include hotel bookings?

    Yes. In addition to deals on St. Louis to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from St. Louis to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Ontario.

  • Can I find deals for business class flights from St. Louis to Ontario?

    Yes. Cheapflights offers flight deals from St. Louis to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

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

    Currently, September is the cheapest month in which you can book a flight from St. Louis to Ontario (average of $236). Flying from St. Louis to Ontario in December is currently the most expensive (average of $298). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

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Top 5 airlines flying from St. Louis to Ontario

Discover the top 5 airlines that operate flights from St. Louis to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,650,959 searches. Data last updated December 2, 2024.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$117Average$203FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$281Average$442FlexibilityNo cancel feeOn-time71%
DeltaCheapest$286Average$346FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$326Average$507FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$341Average$426FlexibilityNo cancel feeOn-time63%
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