The current study examines the effects of consciousness-raising tasks on L2 learners' grammar competence and their flow experiences. The participants consisted of 77 Korean college students who were assigned to two consciousness-raising task groups the hypothesis building/checking and classification and one control group. The study used a background questionnaire, pre-, post-, and delayed English grammar tests, and also pre-, and post-flow perceptions questionnaires. The results indicate that the hypothesis building/checking and classification task groups showed significant improvement in terms of immediate learning effects, while the performance of hypothesis building/checking task was much greater than the control group in terms of long-term retention. As for the flow experiences, learners in the hypothesis building/checking group rated themselves as having a faster flow state than the other groups. Based on the findings, pedagogical implications and suggestions for L2 grammar classrooms have been made.