C$ 187 Find Cheap Flights from St. Louis 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 from St. Louis to Ontario departing on 24/9. 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

KAYAK searches hundreds of travel sites at once for deals on flights to Ontario

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Ontario, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Ontario, as well as popular online travel agencies
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Cheap Flights from St. Louis to Ontario

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis 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 St. Louis to Ontario

Tue, 9 Sep - Sat, 13 Sep
American Airlines Logo
6:10 a.m. - 2:31 p.m.STL-YYZ
7h 21m1 stop
American Airlines Logo
6:30 a.m. - 9:53 p.m.YYZ-STL
16h 23m1 stop
C$ 450American Airlines
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Tue, 9 Sep - Sat, 13 Sep
American Airlines Logo
6:10 a.m. - 2:31 p.m.STL-YYZ
7h 21m1 stop
American Airlines Logo
6:30 a.m. - 1:31 p.m.YYZ-STL
8h 01m1 stop
C$ 451American Airlines
Find Deal
Wed, 6 Aug - Tue, 12 Aug
 Logo
11:24 a.m. - 10:44 p.m.STL-YYZ
10h 20m1 stop
 Logo
6:30 a.m. - 4:31 p.m.YYZ-STL
11h 01m1 stop
C$ 472
Find Deal
Thu, 7 Aug - Sun, 10 Aug
Air Canada Logo
1:30 p.m. - 9:44 p.m.STL-YYZ
7h 14m1 stop
Air Canada Logo
2:15 p.m. - 3:21 p.m.YYZ-STL
2h 06mdirect
C$ 474Air Canada
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Fri, 18 Jul - Tue, 22 Jul
 Logo
10:47 a.m. - 12:29 p.m.STL-YYZ
24h 42m3 stops
 Logo
6:30 a.m. - 4:31 p.m.YYZ-STL
11h 01m1 stop
C$ 488
Find Deal
Sat, 9 Aug - Sat, 9 Aug
Air Canada Logo
9:15 a.m. - 12:15 p.m.STL-YYZ
2h 00mdirect
Air Canada Logo
3:00 p.m. - 8:00 p.m.YYZ-STL
6h 00m1 stop
C$ 508Air Canada
Find Deal
Wed, 3 Sep - Sat, 13 Sep
United Airlines Logo
6:35 a.m. - 5:26 p.m.STL-YUL
9h 51m1 stop
United Airlines Logo
8:20 a.m. - 3:44 p.m.YUL-STL
8h 24m1 stop
C$ 548United Airlines
Find Deal
Mon, 8 Sep - Fri, 12 Sep
United Airlines Logo
5:30 p.m. - 10:40 a.m.STL-YUL
16h 10m1 stop
United Airlines Logo
6:40 p.m. - 10:40 a.m.YUL-STL
17h 00m1 stop
C$ 552United Airlines
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Fri, 18 Jul - Tue, 22 Jul
Delta Logo
5:37 p.m. - 11:10 p.m.STL-YYZ
4h 33m1 stop
Delta Logo
7:24 p.m. - 11:20 p.m.YYZ-STL
4h 56m1 stop
C$ 561Delta
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Thu, 4 Sep - Tue, 9 Sep
Delta Logo
6:00 a.m. - 4:07 p.m.STL-YUL
9h 07m1 stop
Delta Logo
6:00 a.m. - 3:29 p.m.YUL-STL
10h 29m1 stop
C$ 587Delta
Find Deal
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KAYAK's insights & trends for St. Louis to Ontario flights

Get data-powered insights and trends into flights from St. Louis to Ontario to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest St. Louis to Ontario flight route?

The cheapest price for flight routes found by users searching on KAYAK in the last 2 weeks for round-trip flights from St. Louis to Ontario.

The cheapest ticket to Ontario from St. Louis found in the last 72 hours was to Toronto, at C$ 1,141 round-trip. The most popular route is from St. Louis (STL) to Toronto Pearson Intl Airport (YYZ), and the cheapest round-trip airline ticket found on this route in the last 72 hours was C$ 1,141.

Can I save money by flying with a layover from St. Louis to Ontario?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

Yes, flying with a layover may cost you more time, but you can also save money on the route, with a 1 stop layover the cheapest option at C$ 572 on average.

What is the cheapest month to fly from St. Louis to Ontario?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from St. Louis to Ontario, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from St. Louis to Ontario is January, when tickets cost C$ 425 (return) on average. On the other hand, the most expensive months are March and October, when the average cost of round-trip tickets is C$ 795 and C$ 725 respectively.

What’s the cheapest day of the week to fly from St. Louis to Ontario?

The average price of all round-trip flights from St. Louis to Ontario clicked on KAYAK for each day over the last 12 months.

If you are looking for a flight deal from St. Louis to Ontario, look for departures on Thursdays and avoid leaving on a Sunday, as it's usually the priciest day. When flying back from Ontario, Thursday is the cheapest day to fly and Monday is the most expensive.

How far in advance should I book a flight from St. Louis to Ontario?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from St. Louis to Ontario, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below-average price on the flight from St. Louis to Ontario, you should book around 6 weeks before departure. For the absolute cheapest price, our data suggests you should book 23 weeks before departure.


Good to know

Low seasonFebruary
High seasonAugust
Cheapest flightC$ 187
Best time to beat the crowds (19% less expensive on average)
Most popular time to fly (8% more expensive on average)
Flight from St. Louis to Toronto

FAQs - booking Ontario flights

  • How does KAYAK find such low prices on flights from St. Louis 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 St. Louis to Ontario.

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

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

  • What is the Hacker Fare option on flights from St. Louis 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 from St. Louis to Ontario with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from St. Louis 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 from St. Louis to Ontario up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • What is the cheapest time of day to fly to Ontario?

    The cheapest time of day to fly to Ontario is generally in the afternoon, when round-trip flights cost C$ 429 on average. Morning departures are around 13% more expensive than evening flights, on average. The most expensive time of day to fly to Ontario is generally in the morning, which is peak travel time and where the average cost of a ticket is C$ 565.

Reviews of the top airline flying from St. Louis to Ontario

 
See real verified KAYAK customer reviews for airlines flying from St. Louis to Ontario. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from St. Louis to Ontario? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.1
Air CanadaOverall score based on 9678 reviews
7.8Crew
6.3Food
6.8Entertainment
7.1Comfort
7.3Boarding
Airline reviews

Our flight was canceled at the last minute. Someone on the flight said the exact same thing happened to her the day before. I will say they helped us book a flight on another airline so that we could still make our vacation with little delay.

6.0 GoodAnonymous, Jul 2025DCA - YYZ
Read more Air Canada reviews

Our flight was canceled at the last minute. Someone on the flight said the exact same thing happened to her the day before. I will say they helped us book a flight on another airline so that we could still make our vacation with little delay.

We had a very long delay. First the inbound flight took a while, then maintenance, they “fixed it” to then do boarding and leave the gate, and waste a lot of time to have to go back to the gate and eventually deplane. Had to wait for a new aircraft, wait for a gate, and do the whole thing again. Instead of leaving at 9:50am we left until past 1. I could’ve not woken up at 5am, or spend some more time with my family if they gave more grace period of time between flights to give some time in case of any issues. But they have to make all and every dollar possible

Abandoned me in hallway in a wheelchair… which I asked for because I sprained my back. After waiting in the hallway, I decided to walk the rest of the way since someone respecting me up.. My experience with the united was totally the opposite. Wheelchair access, propped swift and save me a lot of grief. Air Canada totally disorganized.

Bad experience boarding and flight got delayed didn’t make it to my next flight

The food on the trip Toronto to Athens could be better: the chicken didn’t taste good.

Conflicting information provided about baggage allowance. One screen said I had a carry on and another said I didnt.

Flight was delayed but the real issue is how long we sat after boarding. Space very limited for an overnight flight and seatbacks didn’t recline so it was almost impossible to sleep.

The staff made sure I was comfortable, moved me to a better seat with more leg room

Somehow, my booking was under my preferred name instead of my legal name so they almost didn’t let me board the plane at LAX. This problem should have been notified to me when I was still in Toronto.

When arriving over 2 hours early to check k in at Charlotte airport I was told I would have to check my carry on ? Apparently the flight was full and may not be room. I was not given a choice and the agent was quite unpleasant about it. I am a senior amd was not comfortable me having to worry about my bag being lost vut it didn’t seem to bother him. There were lots and lots of people of all ages in line when we boarded with carryons and most larger than mine .the rest of my journey was pleasant vut this was totally unacceptable.

Everything you need to know for your flight from St. Louis to Ontario

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