AirHint found the following cheapest return flights from St. Louis (STL) to Paris (CDG) in September 2025 (see full year).

Return flights

08 Sep - 19 Sep	Frontier Airlines
12 Sep - 16 Sep	Frontier Airlines
16 Sep - 26 Sep	Frontier Airlines
10 Sep - 17 Sep	Air Canada
16 Sep - 14 Oct	United
17 Sep - 24 Sep	United
23 Sep - 30 Sep	United
16 Sep - 04 Oct	Frontier Airlines
26 Sep - 06 Oct	Frontier Airlines
25 Sep - 02 Oct	United
15 Sep - 22 Sep	United
29 Sep - 06 Oct	United
27 Sep - 04 Oct	United
06 Sep - 09 Sep	Frontier Airlines
21 Sep - 28 Sep	Air France
19 Sep - 26 Sep	United

Also check the deals for one-way flights from St. Louis to Paris in September.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from St. Louis to Paris in September from $734

Return flights