AirHint found the following cheapest return flights from Porto (OPO) to Oslo (OSL) in September 2025 (see full year).

Return flights

12 Sep - 15 Sep	easyJet
24 Sep - 30 Sep	Norwegian
03 Sep - 06 Sep	Norwegian
24 Sep - 13 Oct	Norwegian	direct
26 Sep - 29 Sep	easyJet
24 Sep - 26 Sep	Norwegian
24 Sep - 06 Oct	Norwegian	direct
12 Sep - 22 Sep	easyJet
24 Sep - 15 Oct	Norwegian	direct
10 Sep - 22 Sep	Norwegian
03 Sep - 22 Sep	Norwegian
03 Sep - 10 Sep	Norwegian
30 Sep - 15 Oct	Ryanair
05 Sep - 08 Sep	easyJet
30 Sep - 18 Oct	Ryanair
24 Sep - 10 Oct	Norwegian	direct
29 Sep - 03 Oct	Ryanair
30 Sep - 19 Oct	Ryanair
24 Sep - 08 Oct	Norwegian	direct
29 Sep - 01 Oct	Ryanair

Also check the deals for one-way flights from Porto to Oslo 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 Porto to Oslo in September from 129€

Return flights