Conflicts over the equitability of transboundary natural resource conservation and management schemes have created barriers to effective policy implementation and practice. In seeking to overcome these barriers in the context of progressing transboundary oceanic fisheries conservation, we explore the divide between equity as defined in principle and as applied in practice in international policy and law. Searching for cross-cutting lessons and themes, we first review multilateral environmental agreements to see how equity is commonly being defined, understood, and then applied in principle. From this analysis, we identify common elements that can facilitate the conceptual framing and application of equitable principles in practice. Framed within these elements, we then explore how applications of equitable principles have performed in two current transboundary conservation and management case studies in regional fisheries management and international climate change policy. From this analysis, we conclude with some lessons learned which show that finding solutions to equity-driven barriers to transboundary conservation, while challenging, are well within our existing capacity to develop and execute.