comes highly recommended for its safety record and because the staff checks your ticket before giving you your luggage back (preventing theft).
Try to book at least the day before travel. Travel agents and guest houses will do this for a US$1-2 fee. Buses tend to leave in the morning or early afternoon. There are also night buses on some routes.
Many buses terminate at an out of town bus station to the east of Siem Reap, from where tuk-tuks are needed to get into the town. This should cost no more than US$2, or maybe US$3 if you're not keen to drive a hard bargain. Anything more will have your driver thinking you are a weak-willed idiot, rather than the generous, naive optimist you perhaps consider yourself to be.
If arriving from the west, consider getting off the bus as it passes through town on National Highway 6, say as it crosses the bridge over the river, before it reaches the bus station. If arriving from the east you have little choice but to face the touts.
Capitol Tours buses, however, terminate at the company's office in the centre of town, near the old market, making them the most sensible choice.
Domestic services
Phnom Penh (US$5)
Kampong Cham
Soung
Battambang (US$3.75)
Sisophon (US$3.75)
Poipet (for Aranyaprathet, the main route into Thailand) (US$3.75)
Anlong Veng (for Ban Pakard in Thailand) (US$4)
Koh Kong (via Phnom Penh, a long journey)
International services
Laos
Pakse (US$30)
Don Det in the 4,000 Islands region (US$35)
Be wary of the sleeper bus from Siem Reap to Vientiane. A second payment may be sought for travel onward after stopping for the border crossing. Unscheduled trip delays and an unexpected change to a different service may occur on-route. Be alert to issues of personal security and watchful concerning your possessions and luggage,
