Centrostephanus rodgersii, the Long-Spined urchin, is a range extending species with a tropical to temperate latitudinal distribution. In Southeast Australia and Tasmania, C. rodgersii has caused considerable kelp forest loss. In Aotearoa New Zealand, the increased range extent and abundance of C. rodgersii overlaps with an already stressed ecosystem due to kelp reduction via endemic urchin (Evechinus chloroticus) grazing, and an increasing number of marine heatwaves driven by climate change. Due to the species’ potential to negatively impact marine ecosystems, fisheries, and livelihoods reliant on marine ecosystem health, C. rodgersii is of interest for understanding how populations respond to ocean climate change and how we might mitigate their impacts. As a tool to assess eco-evolutionary responses of this species, we have assembled a high-quality reference genome, with >98% completeness. This is one of 10 urchin genomes available to date. The reference genome can be used to identify genetic regions undergoing adaptive or evolutionary processes that may contribute to this species’ success in colonising new regions and establishing high abundance. This information can subsequently be used to create monitoring tools of C. rodgersii populations throughout its range, and guide efforts for management and mitigative practices.