This study investigates the protective influence of different resources on the occupational well-being of pre-service teachers during their long-term internship. This research grounded in the theoretical framework of the JD-R model seeks to comprehend how internal resources such as self-efficacy and task-related sense of coherence (SoC) in pre-service teachers along with external resources such as different mentoring styles can foster engagement and mitigate emotional exhaustion. This study introduces the task-related SoC as a novel internal resource in the context of long-term internships to determine its value alongside other resources. The study used a sample of 213 pre-service teachers who answered self-questionnaires at the beginning and end of their four-month-long internship. Structural equation modeling explored the relationships between self-efficacy beliefs, task-related SoC, mentoring approaches, engagement and emotional exhaustion. Results indicate that self-efficacy and task-related SoC significantly predict pre-service teachers’ occupational well-being. Among mentoring approaches, emotional mentoring emerged as the most influential in fostering well-being. The findings confirm the health-promoting effects of self-efficacy and emotional mentoring. This is the first study to apply the general construct of a sense of coherence to the specific context of a long-term internship. It demonstrates that strengthening pre-service teachers’ SoC about particular tasks can be an additional resource for mental health promotion during this period. The results suggest that supporting pre-service teachers in perceiving their internship activities as comprehensible, meaningful and manageable can be beneficial and should be externally promoted by the university.