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

Return flights

25 Sep - 30 Sep	Lufthansa
03 Sep - 10 Sep	Lufthansa
09 Sep - 11 Sep	Lufthansa
16 Sep - 24 Sep	ITA Airways
03 Sep - 01 Oct	Lufthansa
02 Sep - 10 Sep	Lufthansa
25 Sep - 29 Sep	Lufthansa
17 Sep - 24 Sep	Lufthansa
29 Sep - 03 Oct	SWISS
23 Sep - 30 Sep	Lufthansa
23 Sep - 25 Sep	Lufthansa
04 Sep - 10 Sep	Lufthansa
04 Sep - 01 Oct	Lufthansa
02 Sep - 31 Oct	Lufthansa
22 Sep - 01 Oct	SWISS
27 Sep - 06 Oct	ITA Airways
25 Sep - 05 Oct	Lufthansa
02 Sep - 02 Oct	Lufthansa
08 Sep - 01 Oct	SWISS
30 Sep - 16 Oct	Lufthansa

Also check the deals for one-way flights from London to Sofia 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 Sofia in September from $265

Return flights