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

Return flights

12 Dec - 03 Jan	Pegasus Airlines
12 Dec - 16 Dec	Pegasus Airlines	direct
27 Dec - 05 Jan	Pegasus Airlines	direct
18 Dec - 21 Dec	Pegasus Airlines
25 Dec - 29 Dec	Pegasus Airlines	direct
03 Dec - 06 Dec	Air Serbia
12 Dec - 14 Dec	SKY express
28 Dec - 30 Dec	Air Serbia
12 Dec - 03 Jan	Turkish Airlines	direct
28 Dec - 30 Dec	Turkish Airlines	direct
03 Dec - 06 Dec	Turkish Airlines	direct
12 Dec - 21 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 83€

Return flights