The decision of the Supreme Court of India in Republic of Italy v Union of India illustrates the legal and diplomatic complexities that can arise when nations, and states within those nations, have competing claims to jurisdiction over the prosecution of criminal offences. In our increasingly interconnected world, competing claims to jurisdiction are more likely. The decision, among other things, is concerned with legal aspects of coastal state jurisdiction in a federal system and sovereign immunity under international law. This decision is of interest because Australia, like India, is a coastal nation that divides power between federal and state governments. This case note sets out the factual background and legal frameworks that gave rise to the decision, considers the arguments made by each of the parties before the Supreme Court, and summarises the findings of the two presiding Judges. It then seeks to understand the relevance of the decision and any lessons that can be taken from it.