In Croatia, Tomasini families are almost entirely Croats (from Zupanja area ), barely Serbs, and . In the past century, relatively most of Croatian residents bearing this family name were born in Zupanja area and in Rijeka.
Prevalence
About 40 people with faimily name Tomasini live in Croatia today, in 19 households. There were 50 of them in the middle of the past century, and their number decreased by 10 percent. They are located in 6 Croatian counties, in 9 cities and two other places, mostly in Zupanja (10), Rijeka (<10), Jaruge in Zupanja area (<10), Ogulin (<10), and in Cavle in Rijeka area (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1928 in source Emigration Commission Zagreb.