฿4,705 Cheap Flights from St. Louis (STL) to Ontario (ONT)

View ฿4,705 flight on Mon, 5 Jan 2026Opens in a new window

Popular airlines from Lambert-St. Louis International Airport (STL) to Los Angeles - Ontario Intl. Airport (ONT)

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Cheap Flights from St. Louis (STL) to Ontario (ONT)

Prices were available within the past 7 days and start at ฿4,705 for one-way flights and ฿9,540 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Mon, 5 Jan - Sat, 17 Jan
STL
St. Louis
ONT
Ontario
฿9,540 Return, found 1 day ago
฿9,540
Return
found 1 day ago
Select Delta flight, departing Mon, 5 Jan from St. Louis to Ontario, returning Sat, 17 Jan, priced at ฿9,540 found 1 day ago
Delta
Thu, 25 Dec - Sat, 10 Jan
STL
St. Louis
ONT
Ontario
฿10,630 Return, found 1 day ago
฿10,630
Return
found 1 day ago
Select Delta flight, departing Thu, 25 Dec from St. Louis to Ontario, returning Sat, 10 Jan, priced at ฿10,630 found 1 day ago
Delta
Sun, 1 Feb - Wed, 18 Feb
STL
St. Louis
ONT
Ontario
฿10,955 Return, found 1 day ago
฿10,955
Return
found 1 day ago
Select Delta flight, departing Sun, 1 Feb from St. Louis to Ontario, returning Wed, 18 Feb, priced at ฿10,955 found 1 day ago
Delta
Mon, 5 Jan - Sun, 18 Jan
STL
St. Louis
ONT
Ontario
฿11,115 Return, found 1 day ago
฿11,115
Return
found 1 day ago
Select Delta flight, departing Mon, 5 Jan from St. Louis to Ontario, returning Sun, 18 Jan, priced at ฿11,115 found 1 day ago
Delta
Sun, 8 Mar - Tue, 10 Mar
STL
St. Louis
ONT
Ontario
฿11,915 Return, found 1 day ago
฿11,915
Return
found 1 day ago
Select Delta flight, departing Sun, 8 Mar from St. Louis to Ontario, returning Tue, 10 Mar, priced at ฿11,915 found 1 day ago
Alaska Airlines
Sat, 7 Mar - Wed, 18 Mar
STL
St. Louis
ONT
Ontario
฿12,225 Return, found 1 day ago
฿12,225
Return
found 1 day ago
Select Alaska Airlines flight, departing Sat, 7 Mar from St. Louis to Ontario, returning Wed, 18 Mar, priced at ฿12,225 found 1 day ago
Alaska Airlines
Thu, 29 Jan - Sun, 15 Feb
STL
St. Louis
ONT
Ontario
฿12,285 Return, found 1 day ago
฿12,285
Return
found 1 day ago
Select Alaska Airlines flight, departing Thu, 29 Jan from St. Louis to Ontario, returning Sun, 15 Feb, priced at ฿12,285 found 1 day ago
United
Thu, 1 Jan - Sat, 17 Jan
STL
St. Louis
ONT
Ontario
฿12,555 Return, found 1 day ago
฿12,555
Return
found 1 day ago
Select United flight, departing Thu, 1 Jan from St. Louis to Ontario, returning Sat, 17 Jan, priced at ฿12,555 found 1 day ago
Alaska Airlines
Sat, 7 Mar - Sun, 15 Mar
STL
St. Louis
ONT
Ontario
฿12,930 Return, found 1 day ago
฿12,930
Return
found 1 day ago
Select Alaska Airlines flight, departing Sat, 7 Mar from St. Louis to Ontario, returning Sun, 15 Mar, priced at ฿12,930 found 1 day ago
American Airlines
Thu, 1 Jan - Tue, 13 Jan
STL
St. Louis
ONT
Ontario
฿13,515 Return, found 1 day ago
฿13,515
Return
found 1 day ago
Select American Airlines flight, departing Thu, 1 Jan from St. Louis to Ontario, returning Tue, 13 Jan, priced at ฿13,515 found 1 day ago

Find the cheapest month to fly from St. Louis (STL) to Ontario (ONT)

February is typically the cheapest month to fly

From ฿3,803 - ฿14,407 per traveller.
Flight from St. Louis to Ontario route information
Origin airport
Lambert-St. Louis Intl.
Destination airport
Los Angeles - Ontario Intl.
Return price
฿9,540
Distance
2467 km

Perfect flights from St. Louis to Ontario

Embark on an unforgettable journey without breaking the bank with Expedia's incredible deals on cheap flights from St. Louis to Ontario. Whether you're aching for a romantic escape with your partner, craving an adventurous solo expedition, or yearning to immerse yourself in the local history and culture, we've got you covered.
 
Picture yourself strolling through the streets of , surrounded by breathtaking architecture and absorbing the vibrant atmosphere of this captivating city. Indulge in the mouth-watering local specialties, from tantalizing street food to exquisite fine dining. With Expedia, you can experience all of this and more, without sacrificing your budget.
 
Our flexible Lambert-St. Louis Intl. to Los Angeles - Ontario Intl. ticket options cater to your travel preferences, with incredible one-way fares from ฿4,705 and roundtrip prices from ฿9,540. Whether you're planning a short city break or a longer adventure, our dynamic pricing ensures that you find the best deals for your journey.
 
But the magic doesn't stop there. Expedia offers a range of partner services to enhance your trip. Rent a car at Los Angeles - Ontario Intl. and explore and its surrounding areas at your own pace. Discover hidden gems off the beaten path, and create unforgettable memories. We also provide a handpicked selection of accommodations, from charming bed and breakfasts to luxury hotels, ensuring that you have a comfortable and memorable stay.
 
Planning your next great adventure is a breeze with Expedia. Our user-friendly platform, unbeatable prices, and round-the-clock customer support are designed to make your travel experience seamless and stress-free. So, why wait? Book your to travel arrangements today and embark on the journey of a lifetime in Ontario.

Frequently asked questions

How much is a flight from STL to Los Angeles - Ontario Intl. Airport (ONT)?
Based on airfares listed within the last 7 days on Expedia for flights departing within the next year, round-trip flights between St. Louis Lambert International Airport and Ontario Airport start from ฿9,540. Book today to score the best price for your journey. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from Lambert-St. Louis Intl. Airport (STL) to ONT?
Most flights can be cancelled online, but whether you are charged a fee depends on your airline. If you do need to cancel your break, follow the instructions in the Customer Service Portal.
How do I find cheap flights from Lambert-St. Louis Intl. Airport (STL) to Los Angeles - Ontario Intl. Airport (ONT) that have flexible change policies?
Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for STL to Los Angeles - Ontario Intl. Airport (ONT) flights, you'll see a "no change fees" filter for you to select.
How far is the flight from Lambert-St. Louis Intl. Airport (STL) to Los Angeles - Ontario Intl. Airport (ONT)?
The flight distance from St. Louis to Ontario is 2,500 kilometres. Bring a drink, a few snacks and an interesting book to read. Keep yourself entertained and time will zip by.
Which airlines fly direct from St. Louis Lambert International Airport to Ontario Airport?
Unfortunately, there are no airlines that fly direct between Lambert-St. Louis Intl. Airport (STL) and Ontario Airport. You'll need to book a flight with one or more stops.
Are St. Louis Lambert International Airport to Ontario Airport flight tickets cheaper when they're purchased at the last minute?
It is possible to score an amazing last-minute deal from Lambert-St. Louis Intl. Airport (STL) to Ontario Airport, but it's also possible to miss out altogether! As many airlines publish prices up to 12 months in advance, it's worthwhile keeping an eye on fares early and being ready to book when you see a bargain. Expedia compares air carrier prices and updates flight deals regularly, so you can be certain you're always getting the latest offers.

Explore a world of travel with Expedia

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