Buyers from countries which are not members of the EU can purchase the real-estate depending on the rules of reciprocity, under agreements individual countries have made with Republic of Croatia.
Since May of 2014, citizens of the Russian Federation, Ukraine and Serbia can buy real estate on the Croatian territory as a physical person.
At the link below you can see a list of the Ministry of Justice on which are listed the countries which have reciprocity with the Republic of Croatia.