The ongoing biodiversity crisis calls for a complete biodiversity inventory of marine and terrestrial ecosystems. The task is particularly challenging for fragmented island territories, where baseline biodiversity information is often difficult to procure. Using data from the Global Biodiversity Information Facility (GBIF), we curated the first biogeographic dataset for both marine and terrestrial animal species in French Polynesia. These clean dataset centralises information from different sources (museums, research institutions, citizen scientists) that can be used to evaluate species biodiversity information across an understudied region composed of 119 islands and atolls, that belongs to a marine biodiversity hotspot facing conservation challenges. These dataset allowed investigated inherent sampling biases (taxonomic, spatial) and quantified island-specific accessibility biases. Overall, the biases quantified here challenge our ability to conduct biogeographic analyses that integrate the land-sea meta-ecosystem. Our database allows identifying taxa and sampling locations that require urgent attention, as well as comprehensively recorded species that can serve as indicators for environmental degradation. Explicitly acknowledging the inherent biases of biodiversity datasets is the first step towards a more comprehensive characterization of species diversity across fragmented territories. This information is crucial for guiding sound adaptive-management and conservation planning strategies. Detailed results from these analyses will soon be disclosed in a peer-reviewed article.