South Korea has experienced a sheer increase in foreign migrants for the last two decades. Although many scholars accentuate the relative autonomy of contemporary ‘transnational’ migrants, the stream of immigration to South Korea is deeply involved with the changes in central government’s immigration policies in conjunction with socio-economic transformations. First, based on quantitative analysis on immigration data in South Korea, this paper analyzes major changes and tendency of immigration to South Korea for the last two decades. Second, this paper particularly investigates the politico-economic and geographic context of the government? institutional mechanism overarching international migration, which has actively incorporated overseas ethnic Koreans, guest workers, and international marriage migrants. This paper conclusively argues that the immigration policies of the central government of South Korea are dualistically structured: one is to secure flexible unskilled labor, and the other is to attract overseas investment and professional labor.