The coastal and marine ecosystems of South Asia are vital to the region’s economic development, supporting fisheries, tourism, transportation, renewable energy development, and climate regulation. However, these ecosystems face increasing threats from overexploitation, habitat degradation, pollution, and climate change, jeopardizing their ecological balance and economic potential. This review explores the concept of economically synchronized coastal and marine ecosystem protection, focusing on integrating conservation efforts with regional economic priorities to advance a sustainable blue economy in South Asia. Drawing on cases from Sri Lanka, Pakistan, and India, the review highlights successful strategies, including ecosystem-based management, nature-based solutions, and sustainable livelihood initiatives. An action impact matrix (AIM) is used to evaluate interventions based on their ecological and economic impacts, providing a clear framework to prioritize actions. For instance, actions such as implementing marine protected areas (MPAs) and promoting sustainable fishing practices rank highly in both ecological benefits and economic sustainability, while unregulated industrial development demonstrates negative impacts across both dimensions. Particular attention is given to how synchronized regional cooperation can address transboundary challenges, such as overfishing and marine pollution, while promoting shared economic benefits. The review also examines the role of innovative financing mechanisms, in aligning economic incentives with conservation goals. By integrating economic and ecological perspectives and AIM to guide decision-making, this chapter underscores the importance of balancing short-term economic gains with long-term ecosystem resilience. The findings offer actionable insights for policymakers, researchers, and practitioners, providing a framework for harmonizing economic growth with coastal and marine ecosystem protection to achieve a sustainable blue economy in South Asia.