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

Return flights

08 Dec - 15 Dec	Pegasus Airlines	direct
08 Dec - 28 Jan	Air Serbia
23 Dec - 25 Dec	Pegasus Airlines	direct
23 Dec - 30 Dec	Pegasus Airlines	direct
18 Dec - 27 Dec	Aegean Airlines
18 Dec - 27 Dec	Turkish Airlines	direct
08 Dec - 28 Jan	Turkish Airlines	direct
14 Dec - 28 Dec	SKY express
14 Dec - 19 Dec	SKY express
14 Dec - 26 Dec	SKY express
26 Dec - 28 Dec	SKY express

Also check the deals for one-way flights from Istanbul 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 Istanbul to Sofia in December from 101€

Return flights