In line with EU policies, the Danish governmentsees great potentials in aquaculture and wishes to create better growth opportunities for the industry. How this objective can be met while also reducing the environmental impacts of aquaculture and meeting the legal requirements has been a highly debated topic in Denmark, particularly in relation to marine aquaculture (mariculture). This industry has not managed to apply cleaner technologies at the same pace as land-based aquaculture has, and installations have typically been located in coastal areas often already in ecologically poor condition. Recently, the quasi-judicial Environmental Board of Appeal refused to grant an environmental permit for a new mariculture installation. This article reviews the comprehensive and mostly EU-based legal framework regulating Danish mariculture and its application through the decision of the Environmental Board of Appeal. It also touches on the discourse this situation has created and discusses regulatory approaches for reconciling industrial and environmental concerns. Further, it finds that there are limited possibilities of achieving the overall goal of a substantial increase in mariculture production under the current practice of siting mariculture installations near the coast. An obvious solution is to locate mariculture in more open sea areas with greater water flow and depth, and thereby less environmental impact. Locations should be decided on the basis of maritime spatial planning in accordance with the recently adopted EU Maritime Spatial Planning Directive.