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

Return flights

31 Aug - 13 Sep	Shenzhen Airlines
31 Aug - 11 Sep	Shenzhen Airlines
31 Aug - 08 Sep	China Southern
29 Aug - 13 Sep	China Southern
30 Aug - 20 Sep	China Southern
29 Aug - 19 Sep	Shenzhen Airlines
20 Aug - 10 Sep	Austrian Airlines
14 Aug - 14 Sep	Air India
18 Aug - 08 Sep	China Southern
24 Aug - 31 Aug	China Eastern
23 Aug - 05 Sep	Etihad Airways
13 Aug - 14 Aug	Scandinavian Airlines
13 Aug - 15 Aug	Air India
13 Aug - 16 Aug	Air India
19 Aug - 24 Aug	China Southern
14 Aug - 25 Aug	Air India
07 Aug - 14 Aug	China Eastern
19 Aug - 28 Aug	China Southern
22 Aug - 26 Aug	Shenzhen Airlines
07 Aug - 15 Aug	IndiGo

Also check the deals for one-way flights from London to Phnom-penh in August.

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 August from $689

Return flights