On the other hand, once you venture away from the main routes, roads are often little more than a dirt track. These are usually rendered impassable during the rainy season (June-Oct) when large areas of road flood.
The country’s defunct rail network is currently being restored, though don't bank on being able to undertake any grand railway journeys in the near future as it's likely to only carry freight.
Getting between major destinations
Bus
As you’d expect, Phnom Penh is Cambodia’s main transport hub. There’s a whole array of bus companies, services and comfort classes available from here; though most foreigners tend to stick to the 12 or so companies offering ‘VIP’ services. These offer 15-20 seater buses with full air conditioning and go between all of Cambodia’s major towns and cities. Reputable companies include Phnom Penh Sorya Transport Company and Mekong Express.
For a slightly cheaper option, ordinary bus services cover most of the country, have AC and don’t allow standing customers, so you’ll still be in relative comfort. These buses range from about US$4-$6 and sell tickets in advance.
You’ll also notice various private minibuses making journeys around the country. Most of these are a decent enough option, and worth considering if other services are infrequent or full. Don’t confuse these with the sputtering old dust buckets found in more provincial areas - these get full to the brim with people and livestock and will make for a very uncomfortable (though cheap) journey.
Plane
Cambodia Angkor Air flies between Phnom Penh and and Siem Riep 4 times a day. Sadly there are no other internal flight routes anymore, largely due to major improvements in Cambodia’s roads. The same airline also flies twice daily to Ho Chi Minh City in Vietnam.
Tickets need to be booked at least a day in advance at either of their offices (Phnom Penh: House 206A, Preah Norodom Boulevard; Siem Reap: House 17D, Omkhun Street) or online .
Provincial transport
Usually the most convenient way to get between more provincial destinations outside the major bus routes is by shared taxi. These are cheap as you only pay for one seat, though you can hire an entire taxi out for yourself if you want. If you’re going somewhere where the roads are especially bad, particularly in the rainy season, a pick-up truck may be a better idea. It will be a bumpy ride, but you have a choice between paying for a seat in the cab or in the back. If you go for the latter make sure you wrap up your face to avoid the dust and prepare for a sore bottom.
Thanks to the improvement of Cambodia’s roads, boats are a less useful option than they used to be, but nevertheless can serve a purpose in certain situations. There are daily services between Battambang and Siem Reap, though it can be a little rough and you're exposed to the elements. There’s also an express boat down the Mekong from Phnom Penh all the way to the Vietnamese border.
City transport
There is no municipally-run transport in any town or city in Cambodia. Instead, people get around via a number of different transport options including tuktuks, motorbikes and taxis.
Tuktuks in Cambodia essentially consist of a covered trailer attached to the back of a motorbike and were brought in in 2001 after the government banned foreigners from riding more than two to a motorbike. They seat up to six people (though it’s a bit tight with this many) and are a great way to get around town. They can, however, be painfully slow going uphill.
In the biggest cities and tourist areas you’ll find bona fide taxi services. These tend to congregate outside major hotels and are obviously pricier. In the capital, you can call Bailey’s Taxis (012 890000) or Taxi Vantha (012 855000) who are both available 24 hours a day. Expect to pay around US$5 per journey, including to and from the airport.