$122 Find Cheap Flights from St. Louis to Ontario - Compare and Save

In the last 5 days, the lowest price for a flight from St. Louis to Ontario was $122 for a one-way ticket and $191 for a round-trip.

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St. Louis and Ontario are both served by 1 main airport. You will leave St. Louis from Lambert-St Louis and will be arriving at Ontario.

We unfortunately don’t have that data for this specific route.

Star Alliance, and oneworld are the airline alliances operating flights between St. Louis and Ontario, with Star Alliance being the most commonly used for this route.

The two airlines most popular with KAYAK users for flights from St. Louis to Ontario are Southwest and United Airlines. With an average price for the route of $438 and an overall rating of 8.0, Southwest is the most popular choice. United Airlines is also a great choice for the route, with an average price of $520 and an overall rating of 7.4.

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.

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

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 St. Louis with another airline. Booking your flights between St. Louis and ONT can sometimes prove cheaper using this method.

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 St. Louis up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.