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

Return flights

29 Sep - 04 Oct	KLM
27 Sep - 04 Oct	KLM
26 Sep - 03 Oct	KLM
29 Sep - 03 Oct	KLM
23 Sep - 30 Sep	SWISS
27 Sep - 30 Sep	SWISS
27 Sep - 02 Oct	SWISS
25 Sep - 02 Oct	SWISS
20 Sep - 23 Sep	KLM
24 Sep - 01 Oct	KLM
26 Sep - 30 Sep	KLM
29 Sep - 07 Oct	KLM
16 Sep - 23 Sep	KLM
19 Sep - 23 Sep	KLM
29 Sep - 02 Oct	KLM
30 Sep - 03 Oct	KLM
18 Sep - 23 Sep	KLM
25 Sep - 29 Sep	SWISS
20 Sep - 24 Sep	KLM
17 Sep - 30 Sep	SWISS

Also check the deals for one-way flights from London to Prague 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 Prague in September from $259

Return flights