Environmental sampling was conducted at 5 coastal habitats (3 beaches and 2 estuarine habitats) in New South Wales, Australia. Samples were analysed under an eco-genomic approach, in order to assess i) how the microbial assemblages vary at the local scale in accordance to the plant microhabitat (i.e. different parts of the plant) and its surrounding microenvironments (i.e. sediment and seawater), and ii) if seagrass microbial communities differ between environments at the regional scale. Briefly, microbial communities (including bacterial, algae, and fungi taxa) associated to different seagrass microenvironments from all sites, were identified. This information was subsequently coupled with habitat feature data to determine the influence of environmental factors and human-mediated activities on the microbial structure. By comparing the specific composition of different microenvironments and sites, we were able to interrogate the biogeographical conservation of the seagrass microbiome.