This study analyzed questionnaire, pre-test, post-test, and online posts to explore influence of discussion prompts on the competence in English instruction of seven student teachers of elementary school EFL (English as a Foreign Language) in a practicum in Taiwan. This study reached the following conclusions. First, student teachers had good perceptions of the discussion prompts, particularly their effects on reflection on and relevance of English instruction. Secondly, student teachers had good perceptions of discussion prompts because of their clarity; however, they were not satisfied with inactive discussions among participants. Finally, participants' education background and teaching experience affected their perceptions and learning via discussion prompts. A conceptual framework on effective implementations of discussion prompts was suggested.