This Practice-Oriented Short Workshop will highlight the effect of incorporating online one-on-one tutoring sessions with JHS/SHS students for pre-service teachers to develop their teaching English in English. The Japanese Ministry of Education (MEXT) proposed teaching English in English both in JHSs and SHSs to advance students’ English communicative competence. However, preparing for this new policy is a challenge for pre-service teachers because, due to the COVID-19, practice opportunities to teach English have been limited. This workshop will explore how pre-service teachers conducted online one-on-one tutoring sessions about grammar and helped JHS and SHS students learn English through English. To improve JHS/SHS students’ English, prospective teachers used the first session to understand their tutee’s weakness in grammar. The pre-service teachers customized their lessons by creating original worksheets and materials to help their tutee overcome their shortcomings for the second session. Both pre-service teachers and secondary school students enjoyed the benefit of online sessions and showed the progress of their instruction and proficiency, respectively. The presenters will share the procedures and the effect of this collaborative project between the institution and the local school. Participants will leave with ideas for effective grammar instruction in English in regular lessons.