An assessment to remove, partially remove, leave in situ or repurpose oil and gas infrastructure at end of field life can be more robust if it uses rigorous, relevant and accurate data. We used industry remotely operated vehicle (ROV) video, specialised high-definition stereo-video systems and partnered with industry to enhance future ROV campaigns for the collection of scientific data from infrastructure. Data from 17 pipelines and 51 wells were analysed to report on patterns in fish species richness and abundance in Australia’s north, north-west and south-east regions. This represents the largest synthesised data set on marine communities for pipelines and wells, globally. We observed 401 fish species, 350 along pipelines and 113 on well infrastructure. Potential new fish species, critically endangered species, unique behaviours and diverse communities were discovered around pipeline and well infrastructure. Predicting the environmental consequences of different decommissioning options relies on a region-specific understanding of the ecological communities that are associated with these structures. We showcase marine research from around Australia that will inform local decommissioning and contribute to a more comprehensive global understanding of the impact of subsea infrastructure in our oceans.