The “blue economy,” understood broadly as the sustainable use of ocean resources for economic growth, livelihoods and ecosystem health, has become a defining vocabulary through which Indian Ocean states articulate their maritime futures. India and South Africa, the two largest economies bordering the western Indian Ocean and founding members of the Indian Ocean Rim Association (IORA), have each adopted ambitious national blue economy programmes, respectively Sagarmala and the Deep Ocean Mission on the Indian side, and Operation Phakisa on the South African side, and have increasingly framed their bilateral and minilateral engagement (through IORA, IBSA and BRICS) in blue economy terms. Yet the academic literature on IndiaSouth Africa relations remains dominated by trade, diaspora and multilateral diplomacy, and has not systematically examined blue economy cooperation as a distinct and increasingly consequential domain of the relationship. This paper addresses that gap. It asks two questions: what forms does blue economy cooperation between India and South Africa currently take, and what theoretical account best explains both the momentum behind, and the limits of, this cooperation. Drawing on a qualitative documentary and policy analysis of official statements, bilateral agreements and multilateral frameworks, and situating the empirical material within a theoretical framework that combines liberal institutionalist regime theory with critical “blue economy discourse” analysis, the paper argues that India-South Africa maritime cooperation is best understood as an emerging, institutionally thin regime, one driven by converging strategic and developmental interests but constrained by capacity asymmetries, competing blue economy discourses, and the wider geopolitical contest for influence in the western Indian Ocean. The paper concludes that deepening this cooperation will require moving from declaratory convergence toward institutionalised, resourced mechanisms of implementation.