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

Return flights

25 Sep - 29 Sep	SWISS
25 Sep - 30 Sep	SWISS
04 Sep - 11 Sep	SWISS
29 Sep - 03 Oct	KLM
04 Sep - 09 Sep	SWISS
24 Sep - 01 Oct	SWISS
20 Sep - 30 Sep	SWISS
30 Sep - 07 Oct	SWISS
01 Sep - 10 Sep	SWISS
15 Sep - 29 Sep	SWISS
16 Sep - 29 Sep	SWISS
16 Sep - 30 Sep	SWISS
09 Sep - 16 Sep	SWISS
15 Sep - 01 Oct	SWISS
16 Sep - 01 Oct	SWISS
25 Sep - 02 Oct	SWISS
29 Sep - 07 Oct	KLM
29 Sep - 06 Oct	SWISS
30 Sep - 06 Oct	SWISS
17 Sep - 01 Oct	SWISS

Also check the deals for one-way flights from London to Ljubljana 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 Ljubljana in September from $253

Return flights