This article discusses the legal issue of using underwater drones according to international maritime law and Indonesian national law. This discussion is necessary considering the use of underwater drones that cross national borders, there is no specific regulation. Therefore, it is necessary to make special arrangements regarding the use of underwater missiles both in terms of attack, spying, and marine data collection so that foreign countries do not freely operate underwater drones in the territorial sea of ​​other countries and do not violate the right of peaceful passage as regulated. in UNCLOS 1982. The method used is normative legal research which examines the rules and regulations related to the issues discussed. The results of the study show that the government needs to strengthen the maritime security system in Indonesian territory and take firm action against persons involved in the entry of foreign military assets into Indonesian territory.