Background: Early childhood is a critical period for developing emotional and social competencies. SuperKids is a school-based program designed to enhance emotional and social skills in early childhood through play-based activities. Although short-term efficacy has been previously demonstrated, evidence on the maintenance of these gains over time is still limited. Objective: To examine the maintenance of emotional recognition, emotional understanding, and social functioning outcomes in children aged 4 to 6, six months after participating in the SuperKids program. Method: A total of 254 children (44.9% female; 90% Spanish nationality) participated in the study. Measures were administered at three time points: baseline (pretest), immediately after the intervention (posttest), and six months later (follow-up). Measures included tasks on emotional recognition, emotional understanding (including identification of specific emotions such as happiness, anger, sadness, and fear), and social execution. Sociodemographic variables were also collected. Results: From pretest to posttest, statistically significant improvements were found in all outcome domains (p < .001). These gains remained stable at the six-month follow-up, with some indicators even showing continued improvement. Notably, emotional understanding continued to improve between posttest and follow-up (e.g., total score increased from M = 10.79 to M = 11.66, p < .001). Social execution also showed sustained gains (M = 8.53 to M = 8.86, p < .001). Some emotional indicators (e.g., anger recognition) showed small but significant changes at follow-up (p = .02). Conclusion: The SuperKids program produced significant improvements in emotional and social competencies in young children, with gains largely maintained or further enhanced at the six-month follow-up. These findings highlight the potential of early preventive interventions to produce lasting changes in foundational socio-emotional skills during a critical developmental window.