Finding cheap flights to Phnom Penh is often easier when your dates have some flexibility. Demand can rise around Christmas and New Year, Cambodia’s Khmer New Year in April, and other major holiday periods, while the country’s wetter months may offer a wider choice of fares. Weather is still an important part of the decision: Phnom Penh can be hot and humid year-round, but heavier rain between showers may affect sightseeing plans, particularly if you intend to combine the capital with outdoor trips elsewhere in Cambodia.

It is worth searching departures from several UK airports rather than limiting the search to the one closest to home. London airports may provide the broadest range of connecting options, while Manchester, Birmingham and other regional airports can sometimes work better once rail fares, parking and an overnight stay are included. Compare the complete journey, not just the headline fare, checking connection times, baggage rules and whether separate tickets would leave you responsible for arranging a replacement if the first flight is delayed.

Booking well ahead can be sensible for peak travel periods, although keeping an eye on fares over time may reveal better value for less sought-after dates. A midweek departure, a longer connection or an open-jaw itinerary that returns to a different UK airport could reduce the overall cost, provided the saving outweighs extra transport and accommodation expenses.

Flights to Phnom Penh from the UK generally involve at least one connection, so the most suitable itinerary may depend as much on the departure airport as the fare. Travellers in London and the south-east may find a wider choice of connecting itineraries, while regional airports can be more convenient if they avoid a separate journey across the country. When comparing options, look beyond the headline duration: a longer connection at a single airport may be simpler than separate tickets, particularly when checked baggage is involved. Check whether the whole journey is protected on one booking and allow enough time for any airport change.

Phnom Penh’s international airport is outside the city centre, making the final road journey an important part of the arrival plan. Taxis, app-based cars and pre-arranged transfers are practical ways to reach central areas such as the Riverside, Daun Penh or BKK1, although traffic can make arrival times unpredictable. Some searches may also display Siem Reap or other regional gateways as alternatives; these are not Phnom Penh and would require an additional flight or a longer overland journey. Compare the total journey, including onward transport, rather than treating every airport option as interchangeable.