This article analyzes case law on implementation of the norms of international environmental agreements by the federal court of Irkutsk Region, Republic of Buryatia and Zabaykalsky Krai. The goal of this research is to determine the trends of application of international law regimes by the courts. The selected court rulings cover the period from 2017 to 2020. The authors came to the conclusion that the courts typically apply the provisions of the adopted in 1972 Convention on Protection of World Cultural and Natural Heritage. Most commonly used context of its implementation lies in determination of Baykal’s boundaries as the object of world heritage for the purpose of restricting land transferability. Such trend demonstrates strictly prohibitive character of perception of the Convention by law enforcement practice. At the same time, the system of protection of world heritage contains an extensive toolset for solution of environmental and socioeconomic tasks on the objects of world heritage. Practice of implementation of Convention on Biological Diversity (1992) and Ramsar Convention (1971) is quite inconsiderable, which is the authors explain by the goals and tasks of these international agreements. Implementation of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is predictably reduced to introduction of its provisions that determine the protected biological types. The research results can be used in assessing the efficiency of the regimes of international law with regards to protection of Lake Baikal.