Cheap flights from Ontario to St. Louis from C$ 232

The month of January is, on average, the cheapest month to fly to St. Louis from Region of Ontario, with most prices found around C$ 584. If you don’t want to visit St. Louis in January, then you should wait until February to fly from Region of Ontario, when ticket prices are also cheap, with an average price of C$ 590.

Our data shows that Wednesday is the least expensive day to fly to St. Louis. Tickets to fly out on this day can be as low as C$ 627. The most expensive day to fly to St. Louis is Monday, with ticket prices averaging around C$ 824.

The cheapest time of day to fly to St. Louis is at noon when flights can be purchased for as low as C$ 643. If you have a flexible travel schedule, then try to avoid flying in the afternoon when prices are C$ 878 on average. Flights to St. Louis from Region of Ontario in the afternoon are generally more expensive because this time of day is more convenient for travellers’ schedules.

Fly from Toronto Pearson Intl to Lambert-St Louis for the best Ontario - Lambert-St Louis flight prices

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 C$ 712 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 C$ 502 on momondo.

There are 3 cabin classes available to choose from on Region of Ontario to St. Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Air Canada, American Airlines, and WestJet are the most popular carriers operating from Ontario to Lambert-St Louis

Air Canada, United Airlines and American Airlines are the top three most popular airlines that fly to St. Louis from Region of Ontario according to our data. Air Canada is the first choice among our users, with 70% of people opting to fly with this airline when travelling to St. Louis. Keep in mind that there are 3 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

5 flights are operational daily from Region of Ontario to St. Louis as of August 2026. The most popular departure time for this route is 12:00p.m., with 57% of flights per day taking off in the afternoon.

The number of flights available between Region of Ontario and St. Louis is 40 per week as of August 2026. The most frequent departure day is Mon, with 15% of weekly flights leaving on this day.