Antifouling materials aim to prevent the accumulation of marine organisms on surfaces exposed to water, such as ship hulls and offshore structures. Their efficacy not only helps maintain the structural integrity and durability of submerged surfaces but also plays a crucial role in preventing the spread of invasive species and protecting marine ecosystems. This study examined four diverse antifouling paints and a control to assess their performance in the Port Adelaide River, South Australia. Paints were selected to represent different antifouling control mechanisms including: 1) foul release; 2) foul release + biocide; 3) biocide; 4) non antifouling control. All paints were immersed for 4, 14, 25, and 36 weeks in the river, with a fully replicated set of samples also deployed south of the river mouth, at the Cruising Yacht Club of South Australia for comparison. Water quality parameters were monitored fortnightly, and microbial communities in water and on the paints were analysed through flow cytometry, 16S and 18S rRNA gene sequencing and scanning electron microscopy. Immersion duration resulted in significant differences in the fouling organisms to all paints. While all antifouling paints prevented macrofouling throughout the immersion, pre-macrofouling layers were evident on all surfaces. Notably, pre-macrofouling layer attachment decreased between 14 and 25 weeks, indicating a shift in the community composition. This timing would provide a key opportunity for preventative hull grooming, enabling early intervention prior to macrofouling establishment. This study advances understanding of time‑dependent antifouling performance and provides avenues for early control of the settlement of macrofouling organisms.