AirHint found the following cheapest return flights from London (STN) to Phnom-penh (PNH) in September 2025 (see full year).

Return flights

29 Sep - 13 Oct	Ryanair
01 Sep - 15 Sep	Ryanair
15 Sep - 29 Sep	Ryanair
12 Sep - 27 Sep	Pegasus Airlines
25 Sep - 15 Oct	Ryanair
06 Sep - 20 Sep	Pegasus Airlines
16 Sep - 22 Sep	Ryanair
09 Sep - 09 Oct	Ryanair
26 Sep - 04 Oct	Pegasus Airlines
19 Sep - 26 Sep	Pegasus Airlines
26 Sep - 09 Oct	Pegasus Airlines
25 Sep - 16 Oct	Ryanair
20 Sep - 30 Sep	Ryanair
25 Sep - 09 Oct	Ryanair
22 Sep - 06 Oct	Ryanair
01 Sep - 14 Sep	Ryanair
11 Sep - 26 Sep	Ryanair
15 Sep - 26 Sep	Ryanair
13 Sep - 04 Oct	Ryanair
28 Sep - 02 Oct	Emirates

Also check the deals for one-way flights from London to Phnom-penh 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 Phnom-penh in September from 691€

Return flights