Achieving sustainable marine development requires effective governance mechanisms and a collaborative network of institutions capable of shaping efficient policies through the balanced distribution of power and constructive interactions. This study aims to analyze the institutional structure of marine development governance in Iran. The main focus is on identifying patterns of power distribution, the role of key actors, and the nature of interactions among major institutions in the policymaking process. The research methodology is based on a content analysis of the "Comprehensive Program for the Implementation of Marine Development Policies" and a network analysis using the Social Network Analysis (SNA) method. Formal interactions among 28 key institutions were extracted and coded into a binary matrix. Quantitative analysis was conducted using UCINET software by calculating centrality measures (degree, betweenness, eigenvector, and closeness), and network visualization was performed using Gephi software. The findings indicate that the private sector, with the highest levels of out-degree, in-degree, eigenvector, and closeness centralities, occupies a strategic and multifaceted position in the governance structure, playing a pivotal role in decision-making and information transfer. In contrast, institutions such as the Innovation and Prosperity Fund, the Judiciary, and research institutes remain peripheral within the network. This unequal distribution of power undermines institutional cohesion and increases vulnerabilities in inter-organizational coordination. Therefore, redesigning the governance architecture and strengthening the roles of underperforming institutions emerge as critical needs for enhancing the effectiveness of marine development policies in Iran.