These days, there are a couple of easy ways to go from Phnom Penh and Siem Reap and from Siem Reap to Phnom Penh including bus, boat, plane, taxi, and mini-bus.
There are options to fit every budget, but some are nicer than others. Right now the road is in great condition and it’s a smooth ride (fingers crossed it will stay this way). The journey takes between 5 and 6.5 hours, depending on your mode of transport.
There are dozens of bus companies offering service between Siem Reap and Phnom Penh. Many are old, overcrowded and make dozens of stops (but are cheap, running around $6).
In 2012 a new company, Giant Ibis, started running buses between Phnom Penh and Siem Reap and have quickly become the new favorite. They offer WiFi and power outlets on board.
Giant Ibis also has a night bus between Phnom Penh and Siem Reap that runs in both directions at 10:30. The trip takes about 6 hours on both Mekong Express and Giant Ibis.
Tickets cost $13 on Mekong Express for foreigners and $10 for Khmers and $15 on Giant Ibis for all passengers.
Expats in the know seem to travel by mini-bus, as the trip is significantly shorter than by bus. There are many, many mini bus companies covering this route, but we’ve personally vetted the ones below.
Larryta Express runs a fleet of 15-passenger Ford Transit Vans nine times a day between Siem Reap and Phnom Penh. The buses are new and clean. The drivers drive fast, but not terrifyingly and trip takes a little under 5.5 hours, including two stops. Because of the regular departures, you don’t need to purchase tickets more than a day in advance. Tickets cost $8 for Cambodians and $10 for foreigners.
There are now three airlines operating daily flights between Siem Reap and Phnom Penh. This is the fastest (and most expensive) way to travel; if you’re short on time, flying is the best option because it only takes about 45 minutes.
Cambodia Angkor Air is the national carrier and the most expensive option. Flights can be booked online or through any travel agent. The cost is $100+ for a one way flight or $200+ for a round trip. Occasionally travel agents can get better deals, so it’s worth asking.