ONT

$72 Find Cheap Flights from Illinois to Ontario

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight to Ontario departing on 10/4. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

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Flight Deals

Cheap Flights from Illinois to Ontario

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Illinois to Ontario that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Illinois to Ontario

Mon, Oct 20 - Sun, Oct 26
Frontier Logo
9:59 pm - 8:42 pmSTL-ONT
24h 43m1 stop
Frontier Logo
6:53 am - 9:07 amONT-STL
24h 14m1 stop
$144Frontier
Find Deal
Mon, Oct 27 - Mon, Nov 3
Frontier Logo
9:59 pm - 8:42 pmSTL-ONT
24h 43m1 stop
Frontier Logo
4:05 pm - 9:07 amONT-STL
15h 02m1 stop
$145Frontier
Find Deal
Wed, Nov 12 - Sat, Nov 15
Frontier Logo
7:45 pm - 11:10 amSTL-ONT
17h 25m1 stop
Frontier Logo
12:05 pm - 9:07 amONT-STL
19h 02m1 stop
$146Frontier
Find Deal
Thu, Nov 6 - Tue, Nov 11
Multiple Airlines Logo
7:45 pm - 11:50 pmSTL-ONT
6h 05m1 stop
Multiple Airlines Logo
7:20 am - 11:42 pmONT-STL
14h 22m2 stops
$278Multiple Airlines
Find Deal
Tue, Nov 4 - Tue, Nov 11
American Airlines Logo
11:42 am - 6:21 pmSTL-ONT
8h 39m1 stop
American Airlines Logo
6:10 am - 4:27 pmONT-STL
8h 17m1 stop
$281American Airlines
Find Deal
Tue, Dec 9 - Sat, Dec 13
Delta Logo
11:40 am - 7:39 pmSTL-ONT
9h 59m1 stop
Delta Logo
7:05 am - 6:00 pmONT-STL
8h 55m1 stop
$287Delta
Find Deal
Tue, Oct 28 - Wed, Nov 5
American Airlines Logo
7:00 am - 1:43 pmPIA-ONT
8h 43m1 stop
American Airlines Logo
6:10 am - 3:47 pmONT-PIA
7h 37m1 stop
$289American Airlines
Find Deal
Thu, Dec 25 - Tue, Jan 20
Delta Logo
7:20 am - 12:29 pmSTL-ONT
7h 09m1 stop
Delta Logo
1:00 pm - 9:42 pmONT-STL
6h 42m1 stop
$293Delta
Find Deal
Thu, Nov 20 - Mon, Nov 24
Southwest Logo
10:25 am - 3:20 pmSTL-ONT
6h 55m2 stops
Southwest Logo
3:40 pm - 11:35 pmONT-STL
5h 55m1 stop
$312Southwest
Find Deal
Thu, Oct 23 - Wed, Oct 29
Southwest Logo
1:20 pm - 3:35 pmMDW-ONT
4h 15mnonstop
Southwest Logo
8:10 am - 2:00 pmONT-MDW
3h 50mnonstop
$343Southwest
Find Deal

Everything you should know

Cheapest round-trip
$144
Overall average: $346
Frontier
Mon 10/20Sun 10/26
STL - ONT • 1 stop
Cheapest non-stop
$343
Typical prices: $317-434
United Airlines
Mon 10/27Tue 10/28
ORD - ONT • Non-stop
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KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Ontario!
Useful Info

Good to know

Low seasonFebruary
Cheapest flight$72
Best time to beat the crowds with an average 3% drop in price.
Most popular time to fly and prices are also 11% lower on average.
Flight from St. Louis to Ontario

FAQs for booking flights from Illinois to Ontario

  • How does KAYAK find such low prices on flights from Illinois to Ontario?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Illinois to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Illinois to Ontario?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Ontario with an airline and back to Illinois with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Illinois to Ontario?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Ontario from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Everything you need to know for your flight to Ontario

Information on the airport you'll fly into in Ontario

Ontario (ONT)

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