This study aims to examine the legal challenges arising from the transfer of nuclear submarine technology under the AQUOS Treaty (2021) between the United States, the United Kingdom, and Australia. The research method is descriptive-analytical, and the data were collected using library resources and international documents. The main issue of the research is the possible conflict of this treaty with international obligations in the three areas of the law of the sea, the environment, and the nuclear non-proliferation regime. Given Australia's announcement of readiness to participate in multinational military operations in the Strait of Hormuz and the possibility of using a nuclear submarine for this operation, according to Iranian law, the passage is not considered harmless and is contrary to Iranian security and jeopardizes the protection of Iran's marine environment in the Sea of ​​Oman and the Persian Gulf.The findings show that the ACOUS Treaty is inconsistent with Articles 192 and 194 of the 1982 Convention on the Law of the Sea in the field of protecting the marine environment and preventing radioactive pollution. Also, the use of highly enriched uranium fuel and the lack of transparency in nuclear waste management violate the 1996 London Protocol and the precautionary principle, and the transfer of dual nuclear technology to a non-nuclear-weapon state exposes the oversight gaps of the International Atomic Energy Agency and undermines the objectives and principles of the Treaty on the Non-Proliferation of Nuclear Weapons.