As artificial intelligence (AI) is integrated into translation pedagogy, it brings new possibilities for competence development. However, concerns also emerge regarding learner engagement and maintenance of human agency. This study investigates the effects of an AI-Collaborative Translation Workshop on translation major students’ learner engagement and translation competence with a mixed-methods approach. 69 undergraduate translation-major students participated in a 16-week quasi-experimental design. The experimental group (n = 35) attended a structured AI-collaborative workflow, while the control group (n = 34) took a conventional translation course concurrently. Through pre- and post-intervention scales and translation competence tests, quantitative data were gathered, while classroom observations and semi-structured interviews generated qualitative data. According to the ANCOVA results, significantly greater improvements in overall translation performance and engagement were observed in the experimental group. Specifically, the intervention yielded moderate-to-large effects on textual faithfulness and linguistic appropriateness, but the effectiveness of cultural transmission showed no pronounced improvement. In terms of learner engagement, the intervention exerted moderate positive effects on overall engagement, with considerable improvements in behavioral and emotional engagement. No significant change was found in cognitive engagement. Qualitative data corroborated these findings. Students in the experimental group demonstrated more proactive behaviors and positive emotions. Overall, despite strengthening behavioral and emotional participation as well as certain aspects of translation competence, AI-human collaboration still had limited ability to cultivate deep cognitive engagement and culturally sensitive translation skills. Therefore, pedagogical designs should position AI as a resource for critical reflection rather than a substitute for translator decision-making, thereby preserving learner agency and promoting the development of higher-order thinking.