Background: In South Korea, there have been few nationwide epidemiologic studies about premalignant actinic keratosis (AK), squamous cell carcinoma in situ (Bowen’s disease), nonmelanoma skin cancer (NMSC), malignant melanoma of the skin (MM), Kaposi’s sarcoma (KS), connective and soft tissue cancers, or mycosis fungoides (MF). Objective: Using a nationwide population-based study, we attempted to measure the incidence and the prevalence of the above-mentioned tumors in South Korea. Methods: The database we used included all claims in the Korean National Health Insurance program and the Korean Medical Aid program from 2008 to 2016. The International Classification of Diseases, 10th revision (ICD-10) was used to record diagnoses in this database. This data included AK, Bowen’s disease, NMSC, MM, KS, connective and soft tissue cancers, and MF. Results: The age-standardized incidence and prevalence rate of AK, Bowen’s disease, NMSC, MM, KS, connective and soft tissue cancers, as well as MF increased during the periods we investigated. The incidence and prevalence rate of AK and NMSC have increased two- to three-fold. In the case of Bowen’s disease, MM, KS, connective and soft tissue cancers, or MF, we observed no significant tendency in age-standardized incidence or prevalence. Conclusion We confirmed that the age-standardized incidence and prevalence rates of NMSC and AK tended to increase. These results might contribute to developing preventive and therapeutic strategies for skin cancers and may become a source for further studies.