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

Return flights

08 Sep - 15 Sep	Icelandair
01 Sep - 08 Sep	Icelandair
30 Sep - 07 Oct	Icelandair
19 Sep - 09 Oct	Icelandair
24 Sep - 01 Oct	Icelandair
17 Sep - 24 Sep	Icelandair
09 Sep - 16 Sep	United
03 Sep - 10 Sep	United
14 Sep - 23 Sep	Lufthansa
11 Sep - 18 Sep	Icelandair
01 Sep - 08 Sep	SWISS	direct
08 Sep - 15 Sep	SWISS	direct
19 Sep - 26 Sep	United
27 Sep - 04 Oct	United

Also check the deals for one-way flights from Denver 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 Denver to Zurich in September from 513€

Return flights