Assuming that implicit and explicit knowledge are two different constructs, the current study takes unpaired English unaccusatives as its target grammar feature to investigate these two types of knowledge among Korean EFL learners. In line with the growing body of research utilizing a battery of tests, this study adopts a combination of validated tests to assess implicit and explicit knowledge. In doing so, this study lends support to previous studies, in that the L2 learners’ two types of knowledge are not on par. The findings indicate that proficiency was not correlated with the learners’ explicit knowledge, while it was highly correlated with their implicit knowledge. Moreover, regardless of the grammaticality of the unaccsuative sentences, the role of subject animacy varied depending on the learners’ different type of knowledge in relation to proficiency. Finally, a critical discussion on the importance of separating the two constructs of knowledge and implications for future research are provided.