EG and EB Business Visas
With both of these visas, you would initially get an "E-Ordinary"visa on arrival at the airport or border crossing. Note that there is a tourist visa and an E-Ordinary Visa. Both of these are valid for 30 days but the tourist visa cannot be extended. The E-Ordinary visa costs $35 dollars and if you have this visa you can apply for other visas afterwards.
6 month, multiple entry “EG” visa
The EG Visa will give you an additional 6 months in Cambodia and is meant for people who are coming to Cambodia to look for work locally. Towards the end of your 30 days on the E-Ordinary visa, you can apply for the 6 month EG visa at a travel agency in Cambodia. It takes about 5 days to process so leave yourself enough time to make sure that you do not overstay your E-Ordinary visa. You need to provide your passport and a letter stating that you would like to stay in Cambodia to look for work. This is a multiple entry visa and cannot be renewed. If you want to stay longer you need to look at other options such as the EB visa below. Some freelancers have been able to get another EG visa doing visa runs ie. have left Cambodia and when they have come back in have repeated this process of getting an E-Ordinary visa and then a second EG Visa.
6 month to 1 Year Multiple Entry “EB” Business Visa
This visa used to be easy to get and was perfect for freelancers and digital nomads as you didn’t have to show any formal work or business documentation. It is a multiple entry visa and can get renewed over and over again. Unfortunately at the end of 2017 Cambodia tightened the rules to make it only for those who can get a letter of employment from a local company. If you are working locally then you apply for a work permit online here (https://fwcms.mlvt.gov.kh/) It costs $100 per year + $30 for online application + an agency fee if you use a third party (around $70). You also need a medical, proof of residency such as a letter from your landlord. If you are a freelancer or self-employed one way to get this visa is to find some freelance work locally and have that local business write a letter. The letter would need to state that you are working for them as a freelancer.
You can apply for an ER retirement visa even if you are not 55 years of age. If you are under 55 years of age, you need to show proof of income - some say USD$500 per month is enough and some say USD$1000 per month - there are no clear guidelines and believe me I have spoken to many people to try and find out.
It is much easier over 55 as you don't have to show proof of income at all! This may change in the near future!