Kostešić families are Croats and they are mostly from Pula area. In the past century, relatively most of Croatian residents bearing this family name were born in Pula and in Pula area. In Kavran in Pula area every fifth inhabitant had the family name Kostešić.
Prevalence
About 110 people with faimily name Kostešić live in Croatia today, in 50 households. There were 100 of them in the middle of the past century, and their number increased by 10 percent. They are located in threee Croatian counties and 9 other places, mostly in Pula (65), Liznjan in Pula area (10), Rijeka (<10), Zagreb (<10), and in Vodnjan in Pula area (<5).
Outside Croatia
Family name Kostešić (including: Kostesic , Costessich ) is present in 6 countries on three continents. The family name "Kostesic " is used by small number of people in the United States and small number in Australia.
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.