Bibliobattle refers to a social book review game where presenters introduce their favorite book to the audience in a group, and the participants decide the champion book by votes (Taniguchi, 2013). Mini-Bibliobattle is a variation of it with a shorter presentation and discussion period (see Oda, 2018, for the procedure). The study aims to examine the students’ perceptions toward Mini-Bibliobattle and analyze the changes of their scripts throughout the presentations. Approximately 40 university students participated in an 8-week online ER class holding two Mini-Bibliobattles in the L2. Consequently, similar to the previous study by the presenter, participants showed generally positive reactions toward Mini-Bibliobattles and shared interesting books with others. Also, improvements in the presentation were found regarding use of devices such as asking questions. Thus, Mini-Bibliobattle can facilitate learners to read more books and present a favorite book in an attracting manner to the audience.