This brief report delves into the poverty dynamics of second-generation immigrant (G2) children in Sweden and Finland, comparing them with their peers from the majority population. These are unique contexts to examine such socioeconomic inequalities since they are the two highest ranked countries in terms of the Migrant Integration Policy Index. This study draws on longitudinal full-population register data from 2011–2019 for children aged 0–4. This study contributes to existing research by providing a detailed, up-to-date analysis of socioeconomic disparities between a wide range of second-generation immigrant groups and majority children during early childhood—a period widely recognized as critical for development and strongly influenced by work-family reconciliation and family welfare policies. Findings reveal significant inequalities with G2 children facing longer exposure to poverty, higher poverty persistence and higher poverty entry rates than majority children. Interestingly, the G2’s longer exposure to poverty is not due to a higher likelihood of remaining poor, but rather a greater risk of falling into poverty. The study underscores the severe poverty levels among some immigrant groups, G2 Somalis being the chief example, as a critical challenge to equality and social stability in both countries.