There is growing interest in engaging citizen scientists in research and conservation efforts. Citizen scientists can collect data across large spatial and temporal scales that cannot feasibly be covered through traditional research programs. The porcupine ray Urogymnus asperrimus is a rare and poorly understood species that is potentially one of the most vulnerable chondrichthyans to climate change. The ‘Great Porcupine Ray Hunt’ engaged the Australian recreational SCUBA diving community in collecting information on the species’ occurrence, distribution, behaviour and habitat associations. ‘Crowd sourcing’ of recreational diver monitoring effort was achieved through social media (facebook and blogs), diving publications, the internet, email lists, and the Eye on the Reef monitoring program. Recreational divers provided 29 new valid records ranging from Western Australia to the Southern Great Barrier Reef, and even from the Louisiade Archipelago in Papua New Guinea. Submissions also included video footage of foraging and mating behaviour. While relatively few observations were received, the submitted data doubled the number of existing records on the species in Australia, confirmed the species’ rarity, identified potential ‘hot spots’, provided a depth range for the species and extended the species’ range by over 100 km. In doing so, the project demonstrated the potential for citizen scientists to contribute valuable knowledge about rare species, facilitate community education and awareness raising, and provide preliminary data to drive new research projects. Nevertheless, it is crucial to explicitly consider and plan for the potential limitations of Citizen Science before approaching the public to participate in research.