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

Return flights

19 Sep - 22 Sep	Finnair	direct
25 Sep - 28 Sep	Finnair	direct
23 Sep - 27 Sep	Finnair	direct
18 Sep - 21 Sep	Finnair	direct
25 Sep - 26 Sep	Finnair	direct
19 Sep - 21 Sep	Finnair	direct
17 Sep - 19 Sep	Finnair	direct
16 Sep - 17 Sep	Finnair	direct
22 Sep - 30 Sep	Finnair	direct
22 Sep - 25 Sep	Finnair	direct
29 Sep - 01 Oct	Finnair	direct
10 Sep - 23 Oct	Finnair	direct
28 Sep - 02 Oct	Finnair	direct

Also check the deals for one-way flights from Oulu 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 Oulu to Helsinki in September from $112

Return flights