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

Return flights

03 Sep - 10 Sep	United
09 Sep - 16 Sep	United
12 Sep - 26 Sep	Scandinavian Airlines
11 Sep - 18 Sep	United
30 Sep - 07 Oct	United
07 Sep - 14 Sep	United
24 Sep - 01 Oct	United
13 Sep - 20 Sep	United
15 Sep - 22 Sep	United
05 Sep - 12 Sep	United
18 Sep - 25 Sep	United
27 Sep - 04 Oct	United
21 Sep - 28 Sep	United

Also check the deals for one-way flights from St. Louis to Zurich 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 Zurich in September from 575€

Return flights