The institutional analysis of international regimes (e.g., treaties, protocols) is a burgeoning field of study that is foundational to understanding the actor decision-making context in a governance domain where transboundary coordination and behavior standardization substitute for an overarching authority. In the context of global conservation governance, this study uses the Institutional Analysis and Development (IAD) framework’s rule typology and the Institutional Grammar (IG) to compare the regulative de jure institutional design of 45 international conservation policy documents (1,195 institutional statements) from four treaties: the International Convention on the Regulation of Whaling; the Convention on International Trade in Endangered Species, the Convention on Migratory Species, and the Convention on Biological Diversity. The study focuses on monitoring and enforcement mechanisms related to resource appropriation and treaty opt-outs (e.g. reservations/objections), as these represent crucial coordination efforts to thwart biodiversity and related social/economic losses. Findings include (1) the identification of IG syntax “Aims” and “When conditions” that dilute mandatory legally-binding “Deontics”; (2) an institutional divide separating treaty regimes based on the degree of specificity of required/permitted/recommended actions outlined in their norms; and (3) an emphasis on choice versus payoff rules in the enforcement design of U.N.- versus non-U.N.-organized treaties. This study complements existing institutional design, international relations, and legal scholarship by illustrating the IG’s and IAD’s utility to explore de jure regulative institutional monitoring and enforcement design features. It also contributes to a better understanding of formal international conservation governance which may be useful to policy designers and conservation practitioners.