Following the Fukushima nuclear power plant accident, the risk level perceived by Koreans on the radioactive contamination of Japanese food that is being distributed in Korea remains high. Many of these perceptions are based on subjective risk perception rather than an objective measure with scientific evidence, which makes communicating risks more difficult; therefore, it is critical to understand factors associated with risk perception for effective risk communication. In this study, we identified variables that are associated with buying tendencies and opinions about the regulatory policy of Japanese seafood after the accident. A survey was conducted with 1045 adults aged over 20 years in Korea. The majority (68.8%) responded that they would not purchase Japanese seafood when radioactivity levels in the food were non-detectable. Moreover, 82.2% responded that the current levels of import restrictions on Japanese seafood must be maintained. Despite many concerns regarding the exposure to radiation and the effects from food products following the Fukushima accident, the opportunities to encounter and to collect correct information remain limited and average radioactive knowledge scores were low (3.63 out of 9). Of the various characteristics associated with purchase decisions and agreement on the current import restraints of Japanese seafood, trust levels in the government and the mass media for providing information on radioactivity were major factors that influenced risk perception. While the scope of this study was limited to seafood, it is very closely tied to daily lives, where we revealed differences about risk perceptions and agreement on import restraints of Japanese seafood per a complex mixture of individual characteristics and the surrounding environment. These results provide useful information to understand the risk perception of the potential radioactive contamination of food and to predict the public's responses to food consumption and import restraint policies due to nuclear accidents in neighboring countries.