There are several routes of African swine fever (ASF) introduction into a country. Among the possible routes of entry, quarantine policies determine the possibility of introduction by legal import of live pigs and pig products. This study aimed at assessing the probability of ASF introduction through legal import of live pigs and pig products during the high risk period (HRP) using a quantitative stochastic approach during 2009-2018. The result indicates that the mean annual probability of ASF introduction by legal import of live pig was 1.58×10-7 (1.52~1.67×10-7 95% CI). The mean annual probability by legal import of pig products was 1.59×10-10 (1.55~1.64×10-10 95% CI), of which Poland assumed 87.9% of the mean annual risk. The current import quarantine policy of Korean government may be enough to block the release of the virus via legal import of live pigs and pig products, and it should be continually enforced. This result can help to elucidate source of infection and minimize the catastrophic consequences of the potential ASF reintroduction into South Korea by designing risk mitigation strategies such as risk-based selection of routes to be assessed and prevented and decreased exposure possibility by increased control of food waste and swill feeding practices.