BACKGROUND: Universal health coverage (UHC) and global health security (GHS) should be pursued synergistically to strengthen health systems. However, existing studies found that the efforts toward the two agendas were divergent worldwide. We reviewed the synergy status between UHC and GHS in the Western Pacific Region (WPR) to provide evidence for decision-makers to promote synergy. METHODS: We collected the UHC service coverage index (UHC SCI) and the GHS index (GHSI) scores. We created a four-quadrant diagram to discover the gap in UHC and GHS capacities within WPR and divide WPR countries into four groups based on the global mean scores. Further, we adopted global spatial autocorrelation analysis to discover spatial aggregations of high and low scores by calculating Moran's I. In addition, we conducted a correlation analysis to assess the synergy level in WPR and reveal the gap between Pacific Island countries or territories (PICTs) and non-PICTs. We conducted key informant interviews to uncover actual scenarios and address gaps in the quantitative evidence. RESULTS: Compared to the global mean UHC SCI and GHSI scores, nine out of 13 non-PICTs had higher scores, while all 14 of the PICTs had lower scores for both indexes. The Moran's I for WPR countries' UHC SCI and GHSI scores in 2021 were 0.20 and 0.23, respectively (Z-score >
2.58
P <
0.01). The correlation coefficients between the two index scores were 0.722 (P <
0.001) at the global level and 0.869 (P <
0.001) at WPR. Within the WPR, the correlation coefficients were 0.859 (P <
0.001) in the non-PICTs and -0.026 (P >
0.05) in the PICTs. CONCLUSIONS: The synergy level between UHC and GHS was high in the WPR, but this mainly came from the synergy in the non-PICTs. The two agendas have barely synergised the PICTs. To build a safer and healthier WPR, it is important to pay more attention to the countries that have weaker health capacities in the region and narrow the gap.