Let’s start from the beginning, there are no undergrounds in Cambodia and it is hard to find public transport in cities. Everyone use the tuk-tuk to go from one point to another!
Wander around by tuk-tuk
When you will be in large cities such as Phnom Penh and Siem Reap, you will find multiple tuk-tuks willing to take you on a ride around town for a few dollars (you will have to bargain!) Another way to travel around cities in Cambodia is the moto taxi. Tuk-tuks and moto taxis are everywhere in town (even at the airport) any time of the day.
It is also possible to travel by bus around Phnom Penh but buses are hardly used by travelers as they are quite expensive compared to tuk-tuks. We suggest you stay with the same tuk-tuk for the day (it usually cost around 10-15 dollars per day) as the driver will wait for you at each stop and might also be your guide!
Travel around the country
In you wish to travel from a city to another, be prepared to take your time and admire the view! In fact, there are a lot of bus companies that provide trips from one city to another in Cambodia but roads are in poor condition or under construction. It will take you 7 hours from Siem Reap to Phnom Penh (300 kilometers) and from Phnom Penh to Battambang. Count 4 to 5 hours from Phnom Penh to Sihanoukville.
Good to know: Most companies such as Sorya bus and Capitol tours will stop several times on the way to deliver goods and pick up passengers. The journey is, therefore, longer but more authentic! It will cost from 6 to 10 dollars a trip. The company called Giant Ibis is considered as the most luxurious and the fastest one (approximately 15 dollars the trip).
If you don’t have time to take the bus, you can travel by plane. It will take 30 minutes from Siem Reap to Phnom Penh and 45 minutes to Sihanoukville.