AirHint found the following cheapest return flights from Sofia (SOF) to Belgrade (BEG) in September 2025 (see full year).

Return flights

11 Sep - 15 Sep	Air Serbia
12 Sep - 15 Sep	Air Serbia
20 Sep - 23 Sep	Air Serbia
29 Sep - 03 Oct	Air Serbia
04 Sep - 06 Sep	Air Serbia
09 Sep - 12 Sep	Air Serbia
09 Sep - 12 Sep	Air Serbia	direct
12 Sep - 15 Sep	Air Serbia	direct
20 Sep - 23 Sep	Air Serbia	direct
04 Sep - 06 Sep	Air Serbia	direct
01 Sep - 06 Sep	Air Serbia
29 Sep - 03 Oct	Air Serbia	direct
30 Sep - 03 Oct	Air Serbia	direct

Also check the deals for one-way flights from Sofia to Belgrade 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 Sofia to Belgrade in September from 120€

Return flights