AirHint found the following cheapest return flights from Stuttgart (STR) to Helsinki (HEL) in September 2025 (see full year).

Return flights

25 Sep - 30 Sep	KLM
18 Sep - 24 Sep	KLM
25 Sep - 29 Sep	KLM
04 Sep - 09 Sep	KLM
20 Sep - 23 Sep	KLM
30 Sep - 07 Oct	KLM
01 Sep - 24 Sep	KLM
18 Sep - 22 Sep	Lufthansa
25 Sep - 04 Oct	Air France
10 Sep - 17 Sep	Lufthansa
04 Sep - 10 Sep	KLM
02 Sep - 10 Sep	KLM
10 Sep - 10 Oct	Lufthansa
09 Sep - 11 Oct	Lufthansa
27 Sep - 11 Oct	Lufthansa

Also check the deals for one-way flights from Stuttgart to Helsinki 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 Stuttgart to Helsinki in September from 193€

Return flights