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

Return flights

10 Sep - 13 Sep	Vueling Airlines
17 Sep - 20 Sep	Vueling Airlines
06 Sep - 20 Sep	Norwegian
06 Sep - 10 Sep	Vueling Airlines
10 Sep - 14 Sep	Vueling Airlines
09 Sep - 14 Sep	Vueling Airlines
06 Sep - 06 Sep	Norwegian
03 Sep - 20 Sep	Norwegian
23 Sep - 28 Sep	Vueling Airlines
13 Sep - 30 Sep	Vueling Airlines
17 Sep - 04 Oct	Vueling Airlines
17 Sep - 04 Oct	Norwegian	direct
13 Sep - 04 Oct	Norwegian	direct

Also check the deals for one-way flights from Bilbao 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 Bilbao to Oslo in September from $166

Return flights