$82 Cheap Frontier Airlines flights from St. Louis to Ontario (STL to ONT)

Find The Best Day To Fly from St. Louis to Ontario

Amazing Frontier Airlines STL to ONT Flight Deals

The cheapest flights to Los Angeles - Ontario Intl. found within the past 7 days were $151 round trip and $82 one way. Prices and availability subject to change. Additional terms may apply.

ONT From STL Economy Coach Packages on Similar Airlines

Price found within the past 48 hours. Click for updated prices.
Sands Motel
@Marbella Lane - Serene Haven Retreat
Modern Retreat With Spacious Yard Cozy Interiors
Don't see what you're looking for?
See all available trips from Lambert-St. Louis Intl. to Los Angeles - Ontario Intl.
View all trips

Discover our best Frontier Airlines flight from St. Louis STL to Ontario ONT 

To find the best deals on flights to St. Louis from Ontario with Frontier Airlines, just enter your travel dates, filter by Frontier Airlines, and hit search. You’ll find flights to choose from and can sort by price, flight duration, and arrival or departure time.  

 

Return flights from St. Louis STL to Ontario ONT with Frontier Airlines 

If you’re planning a round trip, booking return flights with Frontier Airlines is usually the most cost-effective option. With airfares ranging from $151 to $180, it’s easy to find a flight that suits your budget. Prices and availability subject to change. Additional terms may apply. 

 

Book one-way Frontier Airlines flights from St. Louis STL to Ontario ONT 

A one-way ticket gives you much greater flexibility—allowing you to choose your return date, destination, and time whenever you’re ready. By booking in advance you can find great deals on one-way tickets too. Right now, a one-way Frontier Airlines flight from St. Louis to Ontario costs from $82. Prices and availability subject to change. Additional terms may apply. 

 

The easy way to find cheap flights to Ontario ONT from  St. Louis STL with Frontier Airlines 

To find a cheap Frontier Airlines flight from St. Louis STL to Ontario ONT, sort your search results by price or filter by budget. Thanks to Travelocity’s Price Match Promise, if you find a better airfare deal anywhere else within 24 hours, we’ll credit or refund the difference. 

 

How to find our best airfare deals on Frontier Airlines flights from St. Louis STL to Ontario ONT 

If you’re looking for cheap flights, it helps to be flexible when it comes to your travel dates. You’ll usually find lower cost tickets when you travel during quieter months such as February, or if you book a flight with a stopover. 

 

Find nonstop flights from St. Louis STL to Ontario ONT with Frontier Airlines 

If you’re keen to be on Ontario soil fast, don’t waste time with a stopover—filter your search results to show direct Frontier Airlines flights only. The journey takes around hour(s) min(s) – so you’ll be there before you know it. 

 

Flexible airline tickets for Frontier Airlines flights from St. Louis STL to Ontario ONT 

Make sure you’re not out of pocket if plans change by choosing a flexible ticket with penalty-free amendment and cancellation options. Use our ‘no change fee’ filter to see which flights have this option.  

 

There are a lot of reasons to book your flights to Ontario ONT from  St. Louis STL with Frontier Airlines on Travelocity 

At Travelocity our vast and up-to-the-minute inventory puts all of our best flight deals in one place. So, whether you’re traveling on business or jetting off with friends and family, you can trust Travelocity to get you there.

Frontier Airlines Airports
Hop on a(n) Frontier Airlines flight today by flying to many destinations out of these domestic and international airports:
Airport code
Country
Airport name
Number of flights
DENUSADenver Intl.13
MCOUSAOrlando Intl.7
CUNMEXCancun Intl.6
GDLMEXDon Miguel Hidalgo y Costilla Intl.5
PHLUSAPhiladelphia Intl.2
ORDUSAO'Hare Intl.2
MIAUSAMiami Intl.1
MEXMEXMexico City Intl.1
LASUSAMcCarran Intl.1
LAXUSALos Angeles Intl.1

Travelers ❤️ these 🏨 after their flight to Ontario

DoubleTree by Hilton Ontario Airport

DoubleTree by Hilton Ontario Airport

4 out of 5
222 N Vineyard Ave Ontario CA
This smoke-free hotel features a nightclub and 2 restaurants. Traveling on business? Take advantage of the 24-hour business center, free WiFi in public areas, ...
8.2/10 Very Good! (1,001 reviews)
The room was clean comfortable and quiet.

Reviewed on Jan 25, 2026

DoubleTree by Hilton Ontario Airport
Ontario Airport Inn

Ontario Airport Inn

2.5 out of 5
1801 E G St Ontario CA
This hotel doesn't skimp on freebies - guests receive free buffet breakfast, free self parking, and a free airport shuttle. Traveling on business? Take advantage ...
8.8/10 Excellent! (1,846 reviews)
This hotel is located within walking distance of several restaurants and the shuttle to the airport was handy. The room was clean and the bed was comfortable. It's an older hotel but I wasn't expecting the Ritz so it worked great for me.

Reviewed on Jan 28, 2026

Ontario Airport Inn
Embassy Suites Ontario Airport

Embassy Suites Ontario Airport

3.5 out of 5
3663 E Guasti Rd Ontario CA
This hotel features a restaurant, an indoor pool, and a bar/lounge. Traveling on business? Take advantage of the free WiFi in public areas, express check-out, ...
8/10 Very Good! (1,001 reviews)
Good clean and comfortable room!

Reviewed on Jan 27, 2026

Embassy Suites Ontario Airport
Lowest nightly price found within the past 24 hours based on a 1 night stay for 2 adults. Prices and availability subject to change. Additional terms may apply.
*Price based on the lowest price found within past 24 hours and based upon one night stay for two adults over the next thirty days. Prices and availability subject to change. Additional terms may apply.