The current study aims to examine the effects of implicit learning on Japanese EFL junior college students' writing. The concept of written corrective feedback (WCF) has continued to receive much attention in second language acquisition research. Although most researchers have been supportive of explicit WCF for the development of accuracy, others have focused on implicit WCF with self-correction. While explicit instruction from teachers is the traditional method to provide students with corrective feedback, research in second language acquisition has shown growing interest in the role of implicit learning to improve students' writing skills. To investigate the impact of implicit learning on students' writing, 39 Japanese second-year students who have previously failed a compulsory writing class because of their high absenteeism, participated in this study. As treatments to improve writing skills through implicit learning, implicit tasks and self-correction were used to motivate the students. The design of the experiment includes two types of implicit tasks, implicit error correction and concept mapping during class. In addition, self-correction on homework was implemented. A mix of quantitative and qualitative methods was used in the analysis. The results showed that implicit learning appeared to help students in developing writing skills, but the impact may vary across students with different levels of English proficiency.