Mackerel is one of the most popular fish in Korea. However, the determinants of consumer purchase behaviors have not been identified, even though mackerel is an important fish to Korean consumers. This study aims to predict the determinants affecting consumer purchase intentions for mackerel in the Korean domestic market. For this, the author conducted a questionnaire survey, predicted the consumers’ purchase intentions for mackerel using PLS-SEM (partial least squares structural equation modeling), and evaluated the predictions using the TPB (theory of planned behavior) model. Moreover, this study examined whether there is a difference in consumers’ purchase intentions between Korean and Norwegian mackerel. As a result, it is identified that the quality and utility of exogenous constructs indirectly affected the purchase intention (PI) through attitude toward the behavior (AB). In addition, the PI was affected by the subject norm (SN), which was affected considerably by the industrial conditions (IC) of exogenous constructs. Furthermore, the PI was also influenced by perceived behavioral control (PBC), which has the strongest impact on the PI. However, the purchase determinants of consumers were not different between Korean and Norwegian mackerel. In conclusion, Korean consumers consider quality and utility when they purchase mackerel, and their positive attitude can help them make a purchasing decision. Moreover, the more they recognize the conditions of production, business, and culture, the higher their intention is to purchase mackerel because they are forming a positive social atmosphere. Furthermore, whether they have the financial leeway and repulsion also represents factors in their purchase intention for mackerel. Finally, although Korean consumers prefer domestic seafood, they do not have different preferences when purchasing mackerel.