In order to encourage investment from abroad, the Cambodian government have significantly relaxed the process of obtaining a business visa in recent years.
The initial cost of a business visa (E visa) is US$25 and allows a stay of up to one month. However, the flexibility of the visa system in Cambodia means that a business visa is a viable long term option.
It can be extended indefinitely at the immigration office opposite Phnom Penh airport. Extension costs US$35 for one extra month, US$65 for 3 months, US$125 for 6 months and US$200 for one year. You will have to forfeit your passport for 25 days whilst the extension process is completed and there is a lot of paperwork involved.
There is an alternative, however, it is unofficial. You will get your passport back the next day but you will have to pay a premium. If you decide to pursue the unofficial route, once you have renewed your visa once, renewing it again is fairly hassle free. Going the official route however means that any further extensions are subject to the same long process, however, if you have an employer organising it for you this shouldn’t be a problem. A business visa allows you to exit and enter the country multiple times.
Business visas are also required for those people undertaking casual work and coming to Cambodia as teachers of English.