Cambodia has two types of border crossings, international and local. As you may suspect, international crossings are generally open to all foreign nationalities who are in possession of a valid passport and visa, while local crossings are open only to locals (on each side of the border) who are able to cross back and forth using some form of border pass. The international crossings are the only ones covered in this section.
Cambodia has at least a dozen international overland border crossings. These allow overland travel to Thailand (via six crossings), Laos (via one crossing) and Vietnam (via five crossings). You can also arrive by air at either Phnom Penh or Siem Reap, both of which have international airports, or by sea at Sihanoukville.