The 20th century witnessed populations increasingly concentrated in cities, and this global pattern has persisted into the 21st century. A principal reason for the urban concentration lies in the greater employment advantages offered by bigger metropolises. While this relationship is well documented, few studies have examined whether these benefits differ according to urban dwellers’ birth country. This article analyzes to what extent the migrant–native gap in unemployment and occupational attainment varies according to municipality or city size and, if so, whether that change in inequality is explained by differences in the sociodemographic composition of foreign and native-born populations in big metropolises. Using data from the Spanish General Social Survey, results show that absolute migrant–native labor inequality does vary across city sizes, although in different ways. In larger cities, gross inequality with respect to unemployment seems to be disappearing, whereas in the same places, gross inequality in access to unskilled occupations grows progressively. Controlling for individual, family, and context-related factors explains changes across cities in the unemployment gap, but not in occupational attainment. In other words, big cities do not equalize the risk of unemployment between foreign-born workers and the native-born population but do have a negative impact on equality when it comes to avoiding the occupational ladder's bottom rung. This finding suggests that many international migrants may move to big cities attracted by employment chances, but, in this urban “land of opportunities,” they are more dependent on unskilled jobs and fall into a “trap of precariousness.”