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

Return flights

25 Sep - 30 Sep	KLM
23 Sep - 30 Sep	KLM
30 Sep - 03 Oct	KLM
26 Sep - 30 Sep	KLM
26 Sep - 03 Oct	KLM
26 Sep - 04 Oct	KLM
01 Sep - 30 Sep	Lufthansa
19 Sep - 22 Sep	SWISS
24 Sep - 30 Sep	SWISS
22 Sep - 25 Sep	KLM
16 Sep - 26 Sep	SWISS
26 Sep - 29 Sep	KLM
17 Sep - 20 Sep	KLM
30 Sep - 05 Oct	SWISS

Also check the deals for one-way flights from London 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 London to Belgrade in September from $272

Return flights