AirHint found the following cheapest return flights from Bilbao (BIO) to Sofia (SOF) in December 2025 (see full year).

Return flights

11 Dec - 14 Dec	Vueling Airlines
09 Dec - 12 Dec	Vueling Airlines
12 Dec - 14 Dec	Vueling Airlines
08 Dec - 14 Dec	Wizz Air Malta
16 Dec - 04 Jan	Wizz Air
16 Dec - 05 Jan	Wizz Air
08 Dec - 11 Dec	Wizz Air Malta
20 Dec - 07 Jan	Vueling Airlines
25 Dec - 31 Dec	Vueling Airlines
19 Dec - 05 Jan	Vueling Airlines
27 Dec - 31 Dec	Air Europa
05 Dec - 08 Dec	Volotea
04 Dec - 08 Dec	Vueling Airlines

Also check the deals for one-way flights from Bilbao to Sofia in December.

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 Sofia in December from $148

Return flights