Cognomen Койман (Koiman 
, Kooiman 
, Koyman 
) , in the world, is quite a rare surname. The cognomen Койман is habitual in Netherlands, where it is quite a common surname, New Zealand, where it is a rare surname, and Canada. Not in comparison with a country's population, it is the most numerous in Netherlands, the United States, and Indonesia. Very seldom, Койман is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Koiman | Singapore, Argentina, India, United States, Indonesia |
| Kooiman | Netherlands, Canada, New Zealand, United States, Belgium |
| Koyman | Argentina, India, United Kingdom, Canada, United States |
| Койман | Russia, Kazakhstan, Ukraine |