Singapore reported the elimination of malaria in 1982, but this country remains vulnerable to imported malaria. We describe a large cluster of 16 cases of imported Plasmodium falciparum malaria in visiting Nigerian students. More than half were asymptomatic and diagnosed only on screening. Although early diagnosis and treatment of patients averted local transmission of disease, our report illustrates the vulnerability of malaria-free countries to the introduction of malaria in this age of increasing globalization and ease of travel.