Environmental Impact Assessments for offshore wind farm developments must include a Cumulative Effects Assessment (CEA); due to a lack of standardization or guidance, however, this process varies considerably between projects. The decisions and assumptions made when gathering input data can lead to significant disparity across CEAs. Projects often differ by the zone of influence considered, timelines assessed, sources of data, calculations for the number of animals impacted, etc., all of which result in CEAs that are in no way comparable or informative on a strategic level. This study recommends that guidance be provided so that CEAs can be standardized, more realistic, representative, and comparable. Currently, CEAs combine worst-case scenarios across multiple developments, leading to an assessment that is overly conservative and unrealistic, bearing little resemblance to what is likely to occur in reality. Given the demand and targets for renewable energy, it is strongly advised that the current process be critically reviewed and amended to ensure a more streamlined consenting process going forward.