Cheap Flight Tickets from Ontario (ONT) to St Louis (STL), Starting at $311

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

$311

WN Southwest Airlines • 1 stop • 8h 25m

Aug 14 – Aug 14

The cheapest round trip flight from Ontario to St Louis (ONT-STL-ONT) is currently $311

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Fastest Flight

8h 25m

The fastest nonstop flight from Ontario to St Louis (ONT-STL) takes 8h 25m

Top Airlines Flying from Ontario to St Louis

Southwest Airlines-WN

Southwest Airlines

Delta Airline, DL

Delta Airlines

United Airlines, UA

United 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.

Aug 14 - Aug 14, Economy
WN
Ontario → St Louis
8h 25m
8:10 AM - 3:15 PM • 1 stop
WN
Ontario → St Louis
5h 55m
9:05 PM - 11:00 PM • nonstop
$311
Southwest Airlines
Aug 14 - Aug 14, Economy
WN
Ontario → St Louis
9h 5m
6:20 AM - 2:05 PM • 1 stop
WN
Ontario → St Louis
5h 55m
9:05 PM - 11:00 PM • nonstop
$365
Southwest Airlines
Aug 14 - Aug 14, Economy
WN
Ontario → St Louis
9h 5m
6:20 AM - 2:05 PM • 1 stop
WN
Ontario → St Louis
8h 45m
6:25 PM - 9:50 PM • 1 stop
$367
Southwest Airlines
Aug 13 - Aug 15, Economy
AS
Ontario → St Louis
15h 55m
12:04 PM - 11:59 PM • 1 stop
AS
Ontario → St Louis
15h 7m
6:02 AM - 1:09 PM • 1 stop
$458
Alaska Airlines
Aug 13 - Aug 15, Economy
AS
Ontario → St Louis
12h 34m
2:05 PM - 11:59 PM • 1 stop
AS
Ontario → St Louis
6h 50m
6:00 AM - 8:10 AM • nonstop
$526
Alaska Airlines
Aug 14 - Aug 14, Economy
DL
Ontario → St Louis
11h 52m
7:05 AM - 4:17 PM • 1 stop
DL
Ontario → St Louis
10h 1m
7:45 PM - 11:46 PM • 1 stop
$1076
Delta 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?
NO
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 6:20 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 WN : USD 367
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 2:05 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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