Cheap Flight Tickets from Ontario (ONT) to St Louis (STL), Starting at $172

Good to Know: Cheapest and Fastest ONT - STL Flights

Useful information for finding best airline tickets from Ontario International to Lambert St Louis International on your next trip.

Cheapest Round Trip Flight

$274

WN Southwest Airlines • 1 stop • 10h 30m

Nov 19 – Nov 27

The cheapest round trip flight from Ontario to St Louis (ONT-STL-ONT) is currently $274

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Cheapest One way Flight

$172

WN Southwest Airlines • 1 stop • 8h 25m

Oct 15

The cheapest one way flight from Ontario to St Louis (ONT-STL) is currently $172

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Cheapest Direct Flight

$317

WN Southwest Airlines • nonstop • 5h 25m

Nov 19

The cheapest nonstop flight from Ontario to St Louis (ONT-STL) is currently $317

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Fastest Flight

5h 25m

The fastest nonstop flight from Ontario to St Louis (ONT-STL) takes 5h 25m

Top Airlines Flying from Ontario to St Louis

Southwest Airlines-WN

Southwest Airlines

Delta Airline, DL

Delta Airlines

United Airlines, UA

United Airlines

American Airlines, AA

American Airlines

Alaska Airlines -AS

Alaska Airlines

Latest Flight Deals from Ontario (ONT) to St Louis (STL)

Compare and book low fare round-trip air tickets from Ontario to St Louis. Ideal for travelers with confirmed return itineraries.

Nov 19 - Nov 27, Economy
WN
Ontario → St Louis
10h 30m
6:50 AM - 3:20 PM • 1 stop
WN
Ontario → St Louis
10h 15m
6:30 PM - 10:45 PM • 1 stop
$274
Southwest Airlines
Nov 19 - Nov 27, Economy
WN
Ontario → St Louis
10h 10m
11:40 AM - 7:50 PM • 1 stop
WN
Ontario → St Louis
6h 45m
5:05 AM - 7:10 AM • nonstop
$293
Southwest Airlines
Nov 19 - Nov 27, Economy
WN
Ontario → St Louis
8h 45m
1:45 PM - 9:10 PM • 1 stop
WN
Ontario → St Louis
8h 50m
8:25 AM - 11:55 AM • 1 stop
$303
Southwest Airlines
Nov 20 - Nov 28, Economy
WN
Ontario → St Louis
8h 30m
8:10 AM - 3:20 PM • 1 stop
WN
Ontario → St Louis
18h 55m
9:45 PM - 7:20 AM • 1 stop
$387
Southwest Airlines
Nov 28 - Nov 28, Economy
WN
Ontario → St Louis
13h 25m
5:00 AM - 3:05 PM • 1 stop
WN
Ontario → St Louis
20h 15m
9:45 PM - 8:00 AM • 1 stop
$835
Southwest Airlines
Nov 28 - Nov 28, Economy
WN
Ontario → St Louis
15h 55m
5:50 AM - 5:45 PM • 1 stop
WN
Ontario → St Louis
21h 45m
9:50 PM - 8:55 AM • 1 stop
$1001
Southwest Airlines

Fly from Ontario to St Louis with the Best Airfare Deals on FareLeaders

Looking for a cheap last-minute deal or the best round-trip flight from Ontario to St Louis? Find the biggest savings on one-way and round-trip tickets right here.

FAQs on Ontario to St Louis Flights

What are the airports in Ontario?
ONT
What’s the most popular airline flying from ONT to STL?
The most popular airline flying from Ontario to St Louis are
Can I fly from ONT to STL non-stop?
Yes, you can fly ONT to STL non-stop on
Which airlines fly nonstop between Ontario and St Louis?
The non-stop flights between Ontario and St Louis are .
What’s the earliest departure time from ONT to STL Airport?
The earliest flight leaves ONT at 5:00 am and lands in STL - Lambert St Louis International
What are the airports in St Louis?
STL
Can I make changes to my Ontario to St Louis flight tickets or cancel them on FareLeaders.com?
No. We are an airfare comparison site. All the tickets are booked by the travel agent offering the flight deal and any changes or cancellations to be made are directly done directly by them or the airlines.
Can I cancel my flight tickets from ONT to STL?
Read the fare rules of the Ontario to St Louis air tickets booked. Some airlines allow you to cancel the tickets within a stipulated time period with a cancellation fee.
Which airline alliances offer flights from Ontario and St Louis?
operate flights between Ontario and St Louis
How long does a flight from Ontario to St Louis take?
It takes approximately 4 hour to fly non-stop from ONT to STL, which is 1545.85 miles by air.
Which airlines provide the cheapest flights from Ontario (ONT) to St Louis (STL) ?
In the past couple of days, the cheapest tickets to STL from ONT were found on AA : USD 192
Do I need a passport to fly between ONT and STL?
No
What’s the latest departure time from ONT to STL ?
The last flight leaves ONT at 11:15 pm

Ontario (ONT) to St Louis (STL): Airport Information

Origin Airport Ontario International , Ontario, US
Destination Airport Lambert St Louis International , St Louis, US
Distance 1546 miles

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