The shipping industry is a huge component of the world economy, and although it is often described as an efficient mode of transport, it still contributes as much carbon dioxide to the atmosphere as a major industrialized nation. Efficiency technologies and practices are available that would significantly lessen shipping’s environmental impact, but “amazing loophole[s]” in international environmental law and a set of market failures have prevented them from being widely adopted. These problems have been studied before, but the public regulatory proposals being discussed run into steep, if not insurmountable obstacles. This Note argues that shipping inefficiency can be better addressed through private environmental governance. By operating privately, these forms of governance bypass the problems that traditional public regulation faces, allowing higher efficiency standards to be widely adopted without depending on political will. In so doing, private governance can better align the incentives of consumers, firms, and those firms’ suppliers.