Biological invasions represent a key threat to insular systems, with pronounced impacts across environments and economies. The ecological impacts have received substantial focus, but the socioeconomic impacts are poorly synthesised across spatial and temporal scales. We utilised the InvaCost database, the most comprehensive assessment of published economic costs of invasive species, to assess economic impacts on islands worldwide. We analysed socioeconomic costs across differing expenditure types, and examined temporal trends, across islands that differ in their political geographyisland nation states, overseas territories and islands of continental countries. Over US$36 billion in total costs (including both damages and management) has occurred on islands between 1965-2020 due to invasive species' impacts. Nation states incurred the greatest total and management costs, with islands of continental countries incurring costs of similar magnitude, both far higher than those in overseas territories. Damage-loss costs were significantly lower, but with qualitatively similar patterns across differing political geographies. The predominance of management spending differs from the pattern found for most countries examined and suggests important knowledge gaps in the extent of many damage-related socioeconomic impacts. Nation states spent the greatest proportion of their GDPs countering these costs, at least one order of magnitude higher than other locations. Most costs were borne by authorities and stakeholders, demonstrating the key role of governmental and NGO bodies in addressing island invasions. Temporal trends revealed cost increases across all island types, potentially reflecting efforts to tackle invasive species at larger, more socially complex scales. Nevertheless, the already high total economic costs of island invasions substantiate the role of biosecurity in reducing/preventing IAS arrivals to reduce strains on limited financial resources and avoid threats to sustainable development goals.