Antonci is located in the municipality Grožnjan, in Istra County at an elevation of 105 meters above sea level and it covers the area of 3.31 km² (1.28 sq. miles). According to the 2011 census report, there were 59 inhabitants. It is largely populated by Croats (78%), but also Italians (16%) and Serbs (3%). Nearby places: Završje, Krajići, Vižintini Vrhi, Pirelići, Kostanjica, Sveti Ivan, Makovci, Trombal, Oprtalj and Livade.