<p>Disaster studies often paradoxically frame children as passive victims, overlooking their agency in the context of risk. This study introduces the Pictorial Representation of Illness and Self-Measure for Flood Disaster (PRISM-FD) to map children’s “psychogeographies of risk” in two contrasting Indonesian floodplains. An explanatory sequential mixed-methods design was used. The quantitative phase (<i>N</i> = 314 primary students) assessed risk perception and preparedness in urban (Makassar) and rural (Malang) areas using questionnaires, followed by a qualitative phase using PRISM-FD. Findings revealed “preparedness paradoxes”. Children showed high conceptual knowledge alongside alarming misperceptions. Critically, a gap emerged between household emergency supply possession and children’s access-knowledge, creating an “illusion of preparedness”. School education, while motivating proactive intent, failed pedagogically and did not translate into practical skills. PRISM-FD is effective in visualizing children’s agency, functioning as a novel methodological tool for measuring subjective well-being indicators in high-risk contexts. This study challenges the simplistic “vulnerable victim” narrative, demonstrating that children are motivated actors whose agency is constrained by adult-centric systems. A paradigm shift toward participatory, child-centered DRR is urgently needed to leverage children’s inherent potential as agents of resilience.</p>