Background Skin cancer is a prevalent type of cancer in the UK. Its rising incidence and mortality rates are expected to result in substantial financial implications, particularly on diagnostic and treatment services for skin cancer management in Northern Ireland. Such anticipated disease increases underscore the need for prevention and control measures that should guide policymaking and planning efforts. Methods We conducted a retrospective cost study to measure the burden of skin cancer in Northern Ireland from a healthcare system perspective. Our data-driven model utilized bottom-up methodology and reported 2018 costs using NHS reference unit costs (UK GBP) for skin cancer diagnosis and treatment patient pathways. Sensitivity analyses were performed, including varying diagnostic volumes by applying multipliers for benign cases and assuming a diagnostic conversion rate of 6.8%. An alternative chemotherapy regimen compliance rate was also examined at 75% as compared to base case. Proportional increases were projected based on future estimated increases of 9% and 28% in melanoma cases for diagnostic, treatment, and follow-up volumes specifically related to malignant melanoma. Results As of 2018, NICR recorded 4142 non-melanoma skin cancers (NMSC) and 423 malignant melanoma (MM) cases, averaging 17.5 new patients per trust weekly. The total costs for managing NMSC was GBP1,815,936, whereas that for MM skin cancer costs was GBP12,364,220, out of which GBP8,792,208 accounted for procurement, administration, and chemotherapy drug use. Healthcare providers spent a total of GBP17,024,115 on skin cancer care. Sensitivity analysis suggests diagnostic cost would either reduce by GBP781k to GBP3,061,524 or increase significantly to GBP11,212,183 based on referral volume assumptions. If base case rates rise by 9 or 28% estimated total costs of treating skin cancer will increase to GBP18.1 million and GBP20.4 million respectively. Conclusions Skin cancer management costs in Northern Ireland vary from ~GBP14.3m to GBP26.2m depending on diagnostic referral assumptions. Malignant melanoma costs have risen ~10-fold over the past decade mainly due to chemotherapy costs. A predicted 28% increase in melanoma cases by 2040 would lead to GBP3.3m of additional referral, diagnostic and treatment expenditures, which with inflation adjustment to a further budget requirement of approximately GBP6.4 million by 2022 rates.