Cheap flights from Chicago to St Louis, United States (CHI - STL)

Flying from Chicago to St Louis can be expensive. Our search helps you compare cheap flights, airfare deals, and flight tickets across airlines and agencies so you can book at the best price.

We scan trusted travel agencies and airline booking systems for the route Chicago - St Louis (CHI - STL). We do not sell tickets or add fees - you choose where to buy.

Airfares vary by date, time, and airport. Use filters to find the best option by departure/arrival time, number of stops, airline or alliance, and booking channel.

If your dates are flexible, check the low-fare calendar to find the cheapest days. Booking round-trip in one order often reduces fees, and prices usually rise as departure approaches.

We also recommend you to look through the prices for return tickets from St Louis to Chicago.

Airfares found by our users in the past 24 hours

The cheapest flight from Chicago to St Louis is £92 on Frontier Airlines, departing on 11/02/2026 - 03:07 and returning on 26/02/2026 - 05:17.
The price for these dates could change. Use search to get the best price.

Average round-trip airfares from Chicago to St Louis by months

MonthRound-Trip
January 202631.01 - 11.02from £97
February 202611.02 - 26.02from £92
March 202604.03 - 18.03from £113
April 2026find now
May 2026find now
June 2026find now
July 2026find now
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December 2026find now

Prices shown are based on searches from the last few days. Ticket prices can change and depend on availability at the time of booking.

Airlines are flying from Chicago to St Louis

Southwest Airlines
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