The protection and conservation of the ocean and its resources is currently one of the most pressing issues in the global environmental agenda. Ocean education can play a key role in raising collective understanding of the vulnerability of marine systems and the importance of their protection, and this may best begin with integration of ocean literacy in schools. However, there is little evidence that this is a priority in most formal educational systems around the world. Teachers are the ultimate arbiters deciding whether and how to include ocean education in their classes. Nonetheless, the extent to which marine science may be currently being taught in formal education is still unknown. We used the Australian public school system as a case study to investigate the marine science teaching practices of primary school teachers, through an online survey. Our results suggest that while teachers value the importance of ocean education from a young age, most of them rarely or only occasionally cover marine science topics in their lessons. The most cited requirements by teachers to improve their ocean education practices were a better level of marine science knowledge and a higher availability of ocean-related educational resources.