Nuclear waste is a problem for many countries. A recent case is the nuclear waste from the Fukushima nuclear reactor. The waste was dumped into the Pacific Ocean because the Tokyo Electric Power Company (TEPCO) is no longer able to
accommodate existing nuclear waste. The wastewater of the nuclear waste is a problem for countries surrounding Japan because if the wastewater dump to the sea it become a case of transboundary pollution that pollutes the sea areas of
Japan's neighbouring countries, it is detrimental to the affected countries even though the waste has been treated with the Advance Liquid Processing System (ALPS) process. The Japanese government's actions are controversial because
they have the potential to violate existing international laws, especially the international law of the sea, which will be discussed in this study. Theresearch method used is normative research conducted by examining librarymaterials or secondary data. The conclusion drawn from the data analysed using the deductive method, shows that the Japanese government's actions to dispose of nuclear waste need to be reviewed to prevent the violation of international law concerning environmental protection.