A 31-day voyage to the Gascoyne and Carnarvon Canyon Marine Parks was conducted aboard the RV Investigator in 2022 to describe the species and habitat biodiversity of the area. Using a combination of methods, including acoustic surveys, biological sampling, environmental DNA, and imagery, the full depth range (50m – 5000m) of each park was surveyed across a latitudinal gradient. We present a summary of the diversity collected and describe the dominant and unique habitats and communities observed. A total of 575 teleost fishes, 59 chondrichthyans, and over 2000 invertebrate species were recorded, with 12 new species formally described so far and range expansions across all taxa recorded. The habitats ranged from mesophotic reefs with rich sponge and octocoral assemblages to soft sediment habitat in the deeper sections with either sparsely or densely distributed sessile invertebrates dominated by bryozoans, octocorals, hydroids and sponges, including glass sponges. A rich diversity of mobile invertebrates was also recorded, notably, high densities of pancake urchins and glass scallops. We outline the regional, national and international significance of the collection and present an analysis of spatial patterns of biodiversity across depth and latitudinal gradients. We end by discussing the relevance to marine park management.