Queensland's deep-sea marine invertebrate collections include thousands of registered specimens that have never been officially identified to species level, representing a significant but underutilised resource for biodiversity science. This study quantifies taxonomic identification completeness in Queensland Museum echinoderm records from major historical surveys spanning shallow shelf to abyssal depths (0–4,500 m), integrating data from multiple national biodiversity databases including CSIRO, GBIF, ALA, and OBIS. Results reveal that identification completeness declines significantly with depth, with Holothuroidea showing the lowest odds of species-level identification compared to all other echinoderm classes. Depth-stratified visualisations illustrate this gradient across class composition, completeness heatmaps, rarefaction curves, and temporal trends. Physical examination of the specimens verified database records and generated new identifications for priority taxa. The results identify priority targets for future taxonomic work and deliver improved specimen records to Queensland State Collection, directly contributing to marine biodiversity knowledge and conservation management in the Great Barrier Reef and Coral Sea regions.