Introduction: Conservative treatment in flexible flat foot (FFF) is preferred in most cases; only in symptomatic and conservative-refractory cases is surgical treatment proposed. Subtalar arthroereisis (STA) is a well-established technique, but there remains a paucity of information surrounding the effectiveness and outcome. The aim of this study was to evaluate radiological and functional outcome of STA in FFF. Materials and methods: This study is a case series of 15ft with symptomatic FFF treated by STA from a period of 2018-2024. Mean age at the time of surgery was 10.1±0.83 years. There was a significant increase in both American Orthopaedic Foot and Ankle Society score (AOFAS) and The Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) subjective scoring with p-value of <0.001. Degree of valgus correction was statistically significant (p=0.001). There were significant differences between preand post-operative lateral radiographic measurements with p-value of <0.005. One patient with the lowest radiological angle of correction and increased femoral anteversion had loosened implant in two years follow-up. Results: Despite results in earlier studies, recent evidence, including randomised control trials, supports the reliability of STA in managing FFF, advocating its use over traditional osteotomies due to fewer complications and quicker rehabilitation periods. In our study, all subjects had significant improvement in lateral radiographic measurements and subjective scoring evaluation during follow-up. Conclusion: STA is an option for surgical treatment in symptomatic FFF patients. In this study, all presented subjects showed overall satisfying functional and radiological outcome.