Language testing research has suggested that placement accuracy can be an important factor in the consequences of placement decision-making. However, previous studies primarily have used a one-shot teacher judgment of placement accuracy, suffering from a lack of students' perspectives of their time-varying experiences. The present study aimed to understand the experiences of nine Japanese students who were placed in (in)appropriate levels of English as a foreign language (EFL) speaking course by measuring flow experiences and their fluctuation over time. A flow questionnaire was administered four times during the speaking course, followed by semi-structured interviews at the end of the course. The findings empirically supported the discrepancy between students' flow experiences and the one-short teacher judgment of placement accuracy. The in-depth investigation of students' experiences also suggested two main factors affecting flow experiences: environmental factors and students' attempts to find meaningfulness in their courses. Based on these findings, this study emphasizes the applicability of flow theory to the understanding of test consequences from students' perspectives.