Determine what sort of visa you need. Tourist visas are good for 30 days, whereas business visas, K-visas or diplomatic visas may vary. K-visas are required for people who hold foreign passports, but whose original nationality was Cambodian.
Log on to apply for a Cambodian e-visa. This service, provided by the Kingdom of Cambodia, allows you to apply for a 30-day tourist visa from the comfort of your own desktop. Make sure to confirm that your port of entry and exit accepts e-visa.
Contact your local Cambodian Embassy with any questions. Not only will they be able to answer any questions about the e-visa, but they will also be able to direct you further on if you need a special diplomatic visa or a special K-visa.
Provide your local embassy with all the information required for your particular case: K-visas require extensive documentation, for example, that your parents were Cambodian. As for business visas, you should be able to ask for one at the border for a small fee, and as long as you have a letter of invitation from an in-country sponsor.
