Cheap flights from Ontario to St. Louis from $156
This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to St. Louis departing on 7/19. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
Discover deals from 900+ travel sites with momondo.
Save money when you book flights with momondo
Big names and deals
Big names and deals
Search 100s of travel sites to compare prices.Filter for what you want
Filter for what you want
Free Wi-Fi? Stopover? Instantly customize your results.Trusted and free
Trusted and free
We’re completely free to use - no hidden charges or fees.Price Alerts
Price Alerts
Not ready to book? to track prices.Find the cheapest flights from Ontario to St. Louis
Cheap round-trip flights
Cheap one-way flights
Cheap last minute flights
Cheap direct flights
Delta flights from Region of Ontario to St. Louis
Our best Delta deals on Region of Ontario to St. Louis flight tickets
Air Canada flights from Region of Ontario to St. Louis
Our best Air Canada deals on Region of Ontario to St. Louis flight tickets
See travel insights to St. Louis from
How to get the cheapest flight ticket from Region of Ontario to St. Louis
Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip
What is the cheapest month to fly to St. Louis?
In general, June is the cheapest month to fly from Region of Ontario to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $395. The month of November is another great option to travel to St. Louis, with average flight prices from Region of Ontario averaging around $464.
What is the cheapest day to depart on your flight to St. Louis?
The cheapest day to depart on your flight to St. Louis is on a Saturday when prices can be found for as low as $324. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Sunday because tickets tend to average around $541. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.
What is the cheapest time of day to depart on your flight to St. Louis?
Flying to St. Louis from Region of Ontario in the morning is the least expensive time of day to depart. momondo users have found prices as low as $326 when looking at flights departing in the morning. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $488 per ticket.
What is the cheapest Ontario to Lambert-St Louis flight route?
Fly from Toronto Pearson Intl to Lambert-St Louis for the best Ontario - Lambert-St Louis flight prices
How far in advance should I book a flight to St. Louis?
You are more likely to see cheaper flights to St. Louis from Region of Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $485 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Region of Ontario for as low as $341 on momondo.
What cabin class options are available on Ontario to Lambert-St Louis flights?
There are 3 cabin classes available to choose from on Ontario to Lambert-St Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.
How many flights depart from Region of Ontario to St. Louis on average per day?
As of June 2025, 4 flights take off from Region of Ontario and land in St. Louis each day. The most common flight departure time for this route is 11:00AM, with 50% of daily flights taking off at noon.
How many flights depart from Region of Ontario to St. Louis on average per week?
The number of flights available between Region of Ontario and St. Louis is 30 per week as of June 2025. The most frequent departure day is Wed, with 20% of weekly flights leaving on this day.
Cheap Region of Ontario to St. Louis flight deals and tips
Find info about flight duration, direct flights, and airports for your flight from Region of Ontario to St. Louis
When did momondo last update prices for flights from Ontario to Lambert-St Louis Airport?
Prices for flights from Ontario to Lambert-St Louis Airport refresh daily.
How many operators does momondo search for flights from Ontario to Lambert-St Louis Airport?
As of June 2025, there are 3 operators available to choose from for flights from Ontario to Lambert-St Louis Airport.
How old do you have to be to fly from Ontario to Lambert-St Louis Airport?
The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Ontario to Lambert-St Louis Airport.
What documentation or ID do you need to fly to Lambert-St Louis Airport?
The travel and health documents required for your trip to Lambert-St Louis Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Lambert-St Louis Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.
What is the most popular plane model from Region of Ontario to St. Louis?
Based on momondo bookings for flights between Region of Ontario and St. Louis, the leading plane model is Canadair (Bombardier) Regional Jet 900, making up 55.32% of the total bookings. Other popular models include Airbus A220-300 with 38.96%, Airbus A319 with 1.56%, and Airbus A320-100/200 with 1.56%.
Best airlines flying from Region of Ontario to St. Louis
Compare and see reviews for airlines that fly from Region of Ontario to St. Louis with momondo
| Airline | Rating | Free Cancellation | Price | ||
|---|---|---|---|---|---|
| PriceFrom $324 | Free Cancellation | Rating 7.1 9,568 reviews | |||
| PriceFrom $371 | Free Cancellation | Rating 7.4 8,810 reviews |
Traveling to a place near St. Louis?
Book flights to St. Louis if you plan to visit one of these locationsWhy use momondo?
Why should I use momondo to find a flight deal from Ontario to St. Louis?
momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from Ontario to St. Louis. Millions of users trust and use momondo every year so you are in good hands.
Can I find flights from Ontario to St. Louis with flexible booking policies on momondo?
Flights from Ontario to St. Louis with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.
How can momondo help me find flights from Ontario to St. Louis?
Once all potential Ontario to St. Louis flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.
I’m not ready to book a flight from Ontario to St. Louis right now. Can momondo alert me if prices change?
Price alerts on flights to St. Louis from Ontario are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.