Cognomen Koonstra (Koonstra 
) , around the world, is a rare surname. The surname Koonstra is habitual in Netherlands, where it is a rare surname, and Canada, where it is a very rare surname. Very seldom, Koonstra is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Koonstra | Netherlands, Spain, Canada |