BACKGROUND: Primary tumor thickness is important for prognosis of melanoma patients. To enhance prevention and quantify the true burden of melanoma, better understanding of thickness patterns and associated characteristics is crucial. Previous studies have been limited to report trends and address risk factors of thickness in specific melanoma subtypes in the Greek population. We investigated associations between epidemiological characteristics and thickness for the two most common melanoma subtypes and the trends in thickness over a twelve-year period. METHODS: A retrospective study of 1201 patients with histologically confirmed primary nodular and superficial spreading melanoma (SSM) diagnosed from 2010 to 2021 in "Andreas Sygros" Hospital of Cutaneous and Venereal diseases was conducted. Multiple regression was performed to examine the association of variables of interest with melanoma thickness. RESULTS: SSM thickness significantly increased by 2% per year (percent of change: 2.0, 95% CI: 0.2, 3.7) from 2010 to 2021, while a similar tendency for nodular melanoma (NM) thickness was indicated. Age at diagnosis was demonstrated to be a predictor of thickness for both subtypes. When considering all confounders, overall sun exposure was inversely associated with SSM thickness (PC: -6.2, 95% CI: -12.4, 0.5) and a similar association was indicated for NM (PC: -9.3, 95%CI: -21.1, 4.2). CONCLUSIONS: These results indicate an upward trend of SSM thickness and the associations of age at diagnosis and overall exposure to UV with thickness of both subtypes. Future research is needed to identify additional characteristics and explain differences among all melanoma types.