The 2018 decision by the International Court of Justice (ICJ) in which it for the first time addressed compensation for environmental damage in the case Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v. Nicaragua) – Compensation Owed by The Republic of Nicaragua to The Republic of Costa Rica (‘Costa Rica case’) serves as the perfect opportunity to take stock of where international environmental law stands in terms of liability and compensation for environmental damage. While keeping in mind the distinct features between State responsibility for wrongful acts, the international liability of States in the absence of wrongfulness and the civil liability of persons along with the secondary liability of States as addressed in international treaties (in Part II), this paper seeks to focus on the core elements which one could find at the center of a Venn diagram between these various liability regimes (in Part III), to know: how are international bodies as well as domestic courts, international treaties and national legislations, defining and interpreting environmental damage, and applying it in concrete cases where compensation for environmental damage is in order? What is the standard of care applicable to the no harm obligation – is it based on a fault-based regime, strict or even absolute liability? Which methodology does one apply to calculate environmental harm? Despite some of the progress made with regard to the theoretical aspects of environmental damage, this paper will also review how courts fill in the contours when assessing environmental damages, including their reliance on equity as well as punitive damages when deciding cases, and assess whether international and domestic courts sufficiently rely on independent experts and valuation methods to calculate natural resource damages. In Part IV we will more closely analyze how the weaknesses of the international regime for civil liability for oil pollution has triggered interesting and more robust domestic legislative responses, based on a brief analysis of the Deepwater Horizon oil spill in the United States and the Erika oil spill disaster in France. The red thread running through this paper is that there is a natural and mutual influence between international environmental law developments, be it soft law, treaties or Judgments by the ICJ, and domestic legislative or judicial responses and reasonings. We will be reviewing these various facets through the prism of the Costa Rica case and contrast some of the ICJ’s approaches and conclusions vis-à-vis compensation for environmental damage with responses and methodologies adopted by domestic courts and national legislatures as well as international treaty regimes and international adjudicating bodies. In doing so, we will be able to better place the Costa Rica case in the context of contemporary environmental law developments and identify areas where the ICJ could have walked a more proactive judicial policy path (Part V).