In the recent decade, project-based learning has gained popularity in translator training, with its foundation rooted in the situated learning theory. Advancements in digital technology have opened up new learning opportunities for both teachers and students in translation classrooms. One such opportunity lies in the realm of online communities comprising non-professional translators who create subtitles for videos, movies, TV shows, and various audiovisual materials. This study focuses on a project that integrates the teaching and learning of English speech subtitling within an online translation programme operating on a crowdsourcing model. In contrast to previous studies, which typically emphasised student-centred approaches with minimal teacher involvement, undergraduate students in this study underwent a comprehensive five-week training in subtitling. This training involved the use of instructor-designed worksheets prior to students' active participation in online speech subtitling. The results of pre- and post-tests demonstrated significant improvements in the students' subtitling knowledge and skills. Additionally, feedback from a self-report questionnaire and interviews with selected students highlighted numerous advantages associated with the teacher-guided and collaborative group approach to learning subtitling.