This study aimed to identify the role and nature of spatial visualization in the problem solutions of pre-service teachers solving school-mathematics tasks requiring measurement reasoning. The nuances in the pre-service teachers’ strategies were examined for the role of spatial visualization in the solution process. The findings suggest that inadequacies in visualizing the spatial configurations of the tasks led to incorrect numerical solutions despite the presence of conceptual knowledge. Furthermore, the tendency to rely on formula-based approaches appeared to have suppressed the preliminary spatial processing of the configurations. Theoretically, the paper offers insights into the mechanism that may be involved in the solution of spatially-related mathematical tasks. The findings imply that pre-service teachers need to be sufficiently engaged in spatial reasoning activities.