Nicaragua and Costa Rica have twice turned to the International Court of Justice (ICJ) to resolve disputes related to environmental damage occurring in a transboundary context. In these two cases the Court has to consider at least two issues. The first issue concerns the territorial status of a disputed border area. The disagreement is triggered by natural variations of the San Juan River at the border between the two countries, which causes confusion as to where the State line lies. The second issue concerns environmental damage; more specifically, it involves adversely affected wetlands protected under the Ramsar Convention. The obligations stemming from the Ramsar Convention are of an open-ended character, rendering them difficult to apply. Both issues are connected with the fact that law and the environment have a complicated relationship – that is, legal obligations may be difficult to reconcile with a constantly changing environment. Here, the ICJ has the opportunity to clarify this uneasy relationship.