The research on innovation in the maritime sector has commonly focused on the implementation of innovation rather than on more complex issues such as the interplay between technological aspects, market conditions, and, particularly, regulatory regimes in shaping the emergence and growth of global systems involved with the development, production, and use of environmental innovation. Therefore, this paper sets out to analyze—by combining insights from sectoral (SSI) and technological (TIS) systems of innovation concepts—ballast water treatment systems (BWTS), designed to prevent the negative impacts of invasive species, as an example of such complex interaction. The results show how public policy and institutional acceptance have shaped the market for BWTS. First, BWTS were induced by environmental regulations mandating their use. Second, the demand for BWTS increases substantially when the implementation date of the regulations approaches. Third, differences in regulatory regimes shape the demand for various available technologies. Without coordinated regulations, this unclear operating environment remains a definite concern for shipowners when choosing the specific type of BWTS technology for onboard installation. The results also underline that the combined SSI/TIS framework, utilized in this paper, is a feasible analytical framework for studying environmental innovation.