Sandbanks are marine habitats of conservation importance under the EU Habitats Directive. These habitats are becoming subject to impacts of several human activities including fishing, aggregation extraction, and construction of offshore wind farms that may have detrimental effects on their structure and functioning. We characterised and compared the diversity and biological traits of demersal fish and megafaunal invertebrate assemblages inhabiting three sandbanks, one in the vicinity of a small existing wind farm and two which are proposed sites for future wind farm installations. Samples in the vicinity of the offshore wind farm were compared with two control sites on the same sandbank. There were significant differences in mean number of taxa, abundance and structure of assemblages between sandbanks. However, biological traits analyses (BTA) showed no differences in the functional traits of assemblages among sandbanks, suggesting functional redundancy. Despite a significant spatial variation in structure and Shannon diversity of assemblages between sites within sandbanks, fish and megafaunal assemblage did not differ between sites near wind turbines and the controls. The natural spatial variability in the diversity and biological traits of demersal and megafaunal assemblages inhabiting this naturally highly disturbed environment is larger than any changes associated with the presence of the wind turbines. This study provides important baseline data against which potential future impacts of human activities can be tested.