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

Return flights

24 Sep - 27 Sep	Ryanair
17 Sep - 20 Sep	Ryanair
04 Sep - 08 Sep	Norwegian Air Sweden AOC
17 Sep - 23 Sep	Ryanair
18 Sep - 23 Sep	Ryanair
17 Sep - 24 Sep	Ryanair
11 Sep - 15 Sep	Norwegian Air Sweden AOC
12 Sep - 15 Sep	Ryanair
24 Sep - 01 Oct	Ryanair
19 Sep - 22 Sep	Ryanair
25 Sep - 28 Sep	Ryanair
25 Sep - 03 Oct	Ryanair
25 Sep - 02 Oct	easyJet
29 Sep - 01 Oct	Transavia France
01 Sep - 02 Oct	Ryanair
29 Sep - 02 Oct	Ryanair
25 Sep - 02 Oct	Finnair	direct
24 Sep - 01 Oct	Finnair	direct
01 Sep - 02 Oct	Finnair	direct

Also check the deals for one-way flights from Lisbon 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 Lisbon to Helsinki in September from 163€

Return flights