Island has raised $400 million in a Series F round led by Evolution Equity Partners, lifting its valuation to $6.4 billion, more than double its 2024 level. The financing included Prysm Capital, Sequoia Capital, Coatue Management, Cyberstarts, Insight Partners, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared and Squarepoint, while cybersecurity entrepreneur Dmitri Alperovitch made another personal investment. Island says it will use the capital for product development and international expansion as enterprises deploy AI agents and redesign access to corporate applications and sensitive data. The company, which the financing announcement says was founded in 2022, has about 1,000 employees and says annual recurring revenue has doubled every fiscal year since launch. Island positions its enterprise browser and broader security platform as a control plane for monitoring and governing human and AI-agent activity across identity, data, networks and applications.