You must have a visa and a valid passport to travel to Cambodia. You can only use the visa one month from when you land in Cambodia. However, foreigners visiting the country can get their visa from the Royal Cambodian Embassy, whose validity extends beyond one month from the day of entering the country. Ensure your passport has an official stamp on the day of arrival, and make sure your departure form is kept safe. If you misplace your departure form, you must contact the immigration officials before you set an offer to plan alternative arrangements.