Indonesia has been increasingly susceptible to recent geopolitical developments. Along with the rapid pace of regional arms modernisation and unresolved territorial disputes, it begins to ponder the impact of emerging great power rivalry to the country's strategic interests. However, rather than pursuing a robust military build-up, Indonesian policymakers asserts that diplomacy is the country's first line of defence. This paper argues that Indonesia's defence diplomacy serves two agenda of hedging strategy, strategic engagement and military modernisation. This way, Indonesian defence and security officials seek to moderate the impact of geopolitical changes whilst maintaining the country's defensive ability against regional uncertainties.