Environmental misconduct increasingly extends beyond national borders. However, because of the traditional international law of territoriality, few conventional laws and domestic laws criminalize international environmental misconduct effectively. Because this deficiency must be corrected, international conventions and bodies seek suitable ways of penal enforcement. Following a brief introduction, this Article examines some penal provisions in international environmental conventions. Section III sets forth the process of domestic penal legislation of conventions including the way of shaping environmental criminal law. Several different possibilities for punishing international environmental pollution are then discussed. At the domestic level models of “standardization” and “transnationalization” of environmental criminal law are presented. Section IV will turn to some recent attempts to establish a supranational regulatory authority empowered to penalize core environmental crimes to protect the earth’s shared global commons and preserve the ecosystem. Finally, some concluding remarks will be formulated together with ideas for the further development of international environmental criminal law.