There is no train connection to the airport.
Car and bus
Phnom Penh Airport is located about seven kilometers to the west of the city center. From the city, follow the Confederation de la Russie (Russian Boulevard), which turns into National Road 4 (direction of Sihanoukville), immediately before the intersection with National Road 3 in the direction of Kampot, the airport is located on the left.
There are no bus connections to the airport, Phnom Penh has no city buses.
Car rental - Phnom Penh International Airport
There are car rental companies at the airport. There are no international companies in the whole of Cambodia. There are only local companies that usually rent chauffeur-driven cars.
There are taxis in front of the Arrivals Hall. There is a fixed rate of $9.00 to every destination in the center of Phnom Penh. Since recently, there are also motortaxis (tuktuks) at the airport that charge lower rates, $5.00 to $7.00. Moped taxis are not allowed to pick up passengers at the airport, but you can walk to the exit and hail one. A moped taxi costs $2.00-$3.00, but they will start by asking more.
In front of the terminal building, there is a large parking area, the rate for the first half hour is 1,500 riel, after which it is 1,000 riel per half hour.