The last IUCN Red List assessment for G. japonica was conducted in June 2000. Since then, there has been limited monitoring of wild populations. A notable exception is a capture-mark-recapture study started in 2000 by two researchers at a single field site on Okinawa Island. The researchers have continued to visit the site to the present day and have observed a decline in captures and recaptures; however, no formal analysis of this trend has been conducted. It remains unclear whether this trend is reflective of the broader population across the region. Okinawa Prefecture has undergone significant changes since 2000, including increased urban development, agricultural expansion, infrastructure growth, and rising tourism. These developments, along with threats such as invasive species, smuggling, and environmental contaminants, may be contributing to population declines. To address these uncertainties and improve understanding of the population, we will survey G. japonica across its native range and nearby islands at multiple sites, with support from citizen scientists contributing to data collection. The objectives are (i) to assess the wild populations of G. japonica to update the IUCN Red List status, (ii) develop a Species Action Plan, and (iii) encourage local communities to become involved in turtle conservation.