Despite the growing numbers of volunteer tourists each year, volunteers’ understandings of harm while participating in international volunteering projects have received little attention. I conducted a qualitative study using a mental models approach to explore how volunteers based out of Calgary understand harm before going abroad and after returning from international volunteer trips. I explore how emotions work in these particular spaces and how they impact volunteers’ overall experiences. Gaps in volunteers’ understanding of harm pre- and post-travel were identified and analyzed. Findings suggest that volunteers’ pre-travel understanding of harm was associated with physical harm, however, volunteers’ understanding of harm post-travel tended to be associated with emotional harm. Understanding emotions in volunteer tourism spaces will aid sending organizations in mediating the relationships within and between volunteers in order to understand how harm may be reduced by training, support and outreach programs.