This case study explored what pre-service teachers learned through authentic experiences of English teaching for primary students, drawing upon the concept of a Community of Practice. A total of 21 pre-service teachers engaged in the training project--including planning, preparing, and teaching lessons--and wrote reflection papers after thinking about their activities. The focal data was the pre-service teachers' written work, which was analyzed with a qualitative approach. Follow-up interviews were conducted for selected pre-service teachers. The findings indicated that the project contributed to allowing the pre-service teachers to develop knowledge and skills for primary English education. The study also confirmed that the training project promoted solidarity, especially between the old-timers and the newcomers. On the other hand, the typical Japanese school culture seemed to function as an obstacle to allowing the old-timers and the newcomers to become acquainted enough.