The article offers a fresh perspective on naturalization in the past by taking as a case study colonial Italy between the metropole and its (East and North) African territories from the 1870s to 1941. Building upon recent historiography, and based on new archival materials, the inquiry advances the current scholarly debate as it provides – for the first time – a full discussion linking the two dichotomies ‘citizen/foreigner’ and ‘citizen/indigenous person’ to the question of naturalization; thus, focusing on aliens and colonial natives together, as complex counter-figures to the citizen. Also, the study brings to light hitherto unexplored individual petitions to reflect on naturalization dynamics and to carry out an original investigation that adds a new historical dimension to the multi-disciplinary debate concerning ‘the citizenship–mobility nexus’. In particular, the research throws into sharp relief the ‘crossing of multiple borders’ and the interconnections between the acquisition of Italian citizenship and different forms of mobility in the past and across Italy’s metropolitan and imperial spaces.