One of several papers exploring factors relating to sustainability of integrated coastal management (ICM) in Indonesia, this paper specifically looks at the role of law in promoting ICM sustainability. The paper first paints the general legal landscape governing coastal resources in Indonesia. Specifically, it discusses legal issues specifically relating to management of coastal resources, highlighting the conflicts that arise among the vast body of sectoral laws, and analyzing why those conflicts are so prevalent and so difficult to resolve. It then discusses the recent laws relating to decentralization, and highlights some of the dichotomies created in the effort to delegate management authorities to regional governments within a unitary form of government. The example presented by the establishment of Bunaken National Marine Park in North Sulawesi, and the subsequent donor projects designed to assist in Park planning and management, underscore these legal conflicts and the difficulties in resolving them. Specifically, in creating Bunaken National Park, the central government superimposed an entirely new legal framework on pre-existing regional management, with little socialization or transition. These dichotomous frameworks limited the success of the US AID-sponsored Natural Resources Management (NRM) I Program. With the advent of regional autonomy, and a project design that better accommodated the existing legal realities, the follow-on NRM II was more successful. The paper concludes that, although ICM sustainability is hampered by limitations within the legal framework, project sustainability can still be achieved by recognizing, addressing, and accommodating the legal frameworks in which they will operate.