Only a few people with faimily name Kuster live in Croatia today, in households. There were 20 of them in the middle of the past century, and their number halved. They are located in only threee Croatian places: in Veljun Primorski (<5), Pregrada (<5), and in Homer in Delnice area (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.