There has been an evolving trend in the use of intermittently scanned continuous glucose monitoring (isCGM) among individuals with type 1 diabetes. Although isCGM is proven to be beneficial in the treatment of individuals with type 1 diabetes, its use leads to increasing device costs. This study aimed to investigate the long-term cost-effectiveness of isCGM. Long-term clinical outcomes and costs were projected using the IQVIA Core Diabetes Model (v10.0) based on the observed real-world outcomes of isCGM. The clinical input data for the analysis were sourced from a real-world patient cohort from Eastern Finland, including 877 adult individuals with type 1 diabetes with isCGM (i.e., Freestyle Libre 1 and 2). At the baseline, the patients' mean age was 48 years, and the mean duration of diabetes was 25.8 years. The mean baseline HbA1c was 8.6%, and the mean 12-month change from baseline in HbA1c was -0.37% after the initiation of isCGM. The cost-effectiveness analysis was performed over a lifetime time horizon. A discount rate of 3% was used for the future costs and health outcomes. The projected use of isCGM was associated with improved quality-adjusted life year (QALY) expectancy of 0.84 QALYs after the start of isCGM. The direct lifetime costs were 7861 EUR higher with the use of isCGM, which resulted in an incremental cost-effectiveness ratio of 9396 EUR per QALY gained. According to the present analysis, the use of isCGM is considered cost-effective in adult individuals with type 1 diabetes in a real-world setting in Finland.