$72+ Cheap flights from Ontario to St. Louis (ONT - STL)

For as low as $148, Frontier can have you in St. Louis from Ontario in 5h 31m. The distance from Ontario to St. Louis is about 1541 mi.

Flying on Frontier is currently your cheapest option to St. Louis, with prices starting at $131. Additional round-trip tickets that might be worth considering are offered by Delta and United Airlines, with the lowest prices starting at $139 and $292, respectively. Frontier is priced at 63% lower than the current average price of a flight leaving 3 months from now.

The cheapest airlines for a one-way flight from Ontario to St. Louis are Frontier ($76), Delta ($140), and American Airlines ($158).

Yes. In addition to deals on Ontario to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to St. Louis.

Yes. Cheapflights offers flight deals from Ontario to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

Currently, September is the cheapest month in which you can book a flight from Ontario to St. Louis (average of $71). Flying from Ontario to St. Louis in March is currently the most expensive (average of $220). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.