Background
Open‑source geospatial data and infrastructures are critical for small island states such as Fiji. Geographic dispersion, natural hazard risk, and constrained data resources place high demands on spatial evidence for health decision‑making. Global open-source data now offer levels of completeness, accuracy, and timeliness that can rival some official datasets, enabling new opportunities to address spatial data gaps. However, open data benefits are not evenly distributed. Enhancing the value of open geospatial data requires clear application pathways, institutional collaboration, and capacity building to ensure data supports essential human activities, including service delivery and disaster resilience.

Methods
We demonstrate how open‑source geospatial data can be integrated with national administrative and census‑derived datasets to develop population reference frames, transport network models, and service location registers tailored to the Fijian context. Working in collaboration the Fiji Bureau of Statistics (FBoS), the Pacific Community (SPC), Centre for Australian Research into Access (CARA), Te Ngira Institute for Population Research and Universidad Loyola combined census‑based population grids with open data sources to produce experimental service accessibility metrics.

Results
Fiji is an archipelago of more than 330 islands, with population distribution and service access strongly shaped by geography. Integrating population grids derived from the 2017 Population and Housing Census with open‑source transport and service data has enabled new insights into spatial inequalities in service accessibility. These experimental metrics demonstrate the feasibility of using open data to support evidence‑based planning.

Conclusion
This collaborative case study shows that open‑source geospatial data, when combined with national statistical systems and supported by international cooperation, can substantially enhance service accessibility analysis and resilience planning in small island contexts. Strengthening local capability and institutional partnerships is essential to realising the full value of open data and ensuring equitable, policy‑relevant outcomes under current and future climate risks.