Background: Survival rates for metastatic melanoma (MM) patients have improved in recent years, leading to major expenses and health resource use. We conducted a non-concurrent prospective study to describe the burden of hospitalization in a real-world setting for patients with MM. Methods: Patients were tracked throughout all hospital stays in 2004–2019 by means of hospital discharges. The number of hospitalizations, the rehospitalization rate, the average time spent in the hospital and the time span between consecutive admissions were evaluated. Relative survival was also calculated. Results: Overall, 1570 patients were identified at the first stay (56.5% in 2004–2011 and 43.7% in 2012–2019). A total of 8583 admissions were retrieved. The overall rehospitalization rate was 1.78 per patient/year (95%CI = 1.68–1.89); it increased significantly with the period of first stay (1.51, 95%CI = 1.40–1.64 in 2004–2011 and 2.11, 95%CI = 1.94–2.29 thereafter). The median time span between hospitalizations was lower for patients hospitalized after 2011 (16 vs. 26 months). An improvement in survival for males was highlighted. Conclusions: The hospitalization rate of patients with MM was higher in the last years of the study. Compared with a shorter length of stay, patients were admitted to hospitals with a higher frequency. Knowledge of the burden of MM is essential for planning the allocation of healthcare resources.