Mariculture—the farming of marine organisms—has become a central pillar of global seafood production, yet its rapid expansion poses complex sustainability challenges related to environmental degradation, regulatory gaps, and social equity. This chapter examines how legal and policy frameworks can support a more sustainable, inclusive, and technologically advanced mariculture sector, focusing on Vietnam as a key case study. Drawing on international legal instruments such as the United Nations Convention on the Law of the Sea, Sustainable Development Goal 14, and the FAO Code of Conduct for Responsible Fisheries, the chapter explores how global sustainability norms are operationalized through national governance regimes. Using comparative analysis, it evaluates governance models in Norway, the European Union, and Indonesia—highlighting best practices in marine spatial planning, licensing and permitting systems, stakeholder participation, and environmental safeguards. The chapter then turns to Vietnam’s evolving mariculture governance landscape, assessing recent legal reforms, policy strategies, and institutional frameworks. Case studies from Quang Ninh and Khanh Hoa provinces illustrate both progress and persistent challenges in spatial planning, technological modernization, and ecological oversight. Based on this analysis, the chapter offers practical recommendations for strengthening Vietnam’s mariculture governance, including adaptive licensing, GIS-based MSP tools, public-private innovation partnerships, and formalized comanagement mechanisms. It also outlines how Vietnam’s hybrid approach—combining smallholder systems with emerging offshore development—offers replicable lessons for other coastal nations. Ultimately, the chapter contributes to global discourse on sustainable blue economy strategies and the role of law in shaping resilient mariculture systems.