BACKGROUND: Child sexual abuse (CSA) is a major public health concern, yet rigorously evaluated and fully manualized primary prevention programs for preschool children remain scarce. Evidence on the feasibility and acceptability of such interventions among young children and their educators is limited. OBJECTIVE: This study assessed the acceptability, safety, and feasibility of the CARE Program, a CSA primary prevention intervention for preschool children in Portugal and explored changes in CSA-related knowledge. PARTICIPANTS AND SETTING: Participants were 195 preschool children aged 3 to 6 years from five schools and five educators from three schools in northern and central Portugal. METHODS: A pragmatic, parallel-arm, waitlist-controlled mixed-methods design was used. Quantitative pre-post assessments examined children's CSA-related knowledge using a vignette-based instrument and evaluated program acceptability. Qualitative interviews with educators explored feasibility, safety, and perceived impact through framework analysis. RESULTS: The CARE Program demonstrated high levels of acceptability and safety among both children and educators. Feasibility indicators were favorable, with strong adherence and retention, although recruitment at the school level proved challenging. Preliminary findings indicated significant improvements among children in the intervention group in emotional recognition and rejection of secrecy, whereas no comparable changes were observed in the control group. Findings related to disclosure were less consistent across analytic approaches and should be interpreted with caution. CONCLUSIONS: The CARE Program appears to be a safe, acceptable, and feasible primary prevention strategy for preschool children in Portugal. Preliminary evidence supports its potential to improve CSA-related knowledge and justifies further evaluation in a fully powered cluster randomized controlled trial.