Operational expenditure (OPEX) incurred during the Operations and Maintenance (O&M) phase accounts for between 20% and 30% of the Levelised Cost of Energy (LCOE) of an offshore renewable energy development over its lifetime. O&M simulation software tools can be used to derive OPEX estimates, along with other Key Performance Indicators (KPIs) such as asset availability. These tools are becoming increasingly common in the industry as they can also help optimise O&M strategies and improve asset management. This paper looks to explore: