The Turtle Cooling Project was established in late 2018 by WWF-Australia and partners due to the feminization of the Northern Great Barrier Reef (nGBR) green turtle (Chelonia mydas) population. Turtles have temperature-dependent sex determination, meaning that warmer nests produce more females, and cooler nests produce more males. The nGBR discovery revealed an urgent need to understand if other important rookeries may also be experiencing feminization, and if, how and when intervention actions may be necessary. This project is now in its fifth year, and by utilizing innovative approaches, has determined how to cool nests, including in regional areas where freshwater may not be available. The operational-sex ratio has been investigated, to identify what proportion of males to females is needed to continue a viable population, and additionally, we have determined that a one-off, relatively brief, cooling event during the middle of the sex determining period can increase the proportion of male hatchlings produced at otherwise female producing temperatures. Now, the team is exploring which important rookeries across the Asia Pacific are susceptible to feminization, using predictive models to anticipate if, and when local managers may need to utilize turtle cooling methods.