Background/Objectives: Melanoma is a malignant tumour of melanocytes. Cutaneous melanoma accounts for the vast majority of cases and has benefitted from advances in targeted and immune checkpoint inhibitor therapies, leading to substantial improvements in survival. In contrast, mucosal and vulvovaginal melanomas are rare, aggressive subtypes with distinct molecular and immune profiles and poor prognoses. This review synthesises evidence comparing cutaneous, mucosal, and vulvovaginal melanoma, with emphasis on biology, treatment, and outcomes Methods: A narrative comparative review was undertaken, examining the published literature on the epidemiology, molecular and immune characteristics, and treatment outcomes of cutaneous, mucosal, and vulvovaginal melanoma, including systemic therapies and surgical approaches. Results: Cutaneous melanoma demonstrates high tumour mutational burden and frequent BRAF and NRAS mutations, underpinning the success of targeted therapy and immunotherapy. Mucosal and vulvovaginal melanomas exhibit lower mutational burden, distinct mutation patterns, and reduced immunogenicity, correlating with poorer treatment responses. Surgery remains the mainstay of management, though optimal margins in vulvovaginal melanoma are unclear. Recurrence rates are high, and five-year survival remains poor. Evidence for systemic therapy is limited to small retrospective cohorts and subgroup analyses, showing lower response and survival rates compared with cutaneous melanoma. Chemotherapy has minimal benefit. Conclusions: Mucosal and vulvovaginal melanomas are biologically and clinically distinct from cutaneous melanoma and continue to have poor survival outcomes. Their rarity restricts high-quality evidence, highlighting the need for collaborative, innovative research to inform effective treatment strategies.