This study aims to analyze the law enforcement against illegal fishing as a transnational crime. The research method used is normative juridical. The results showed that illegal fishing as a type of transnational crime is due to its elements involving more than one country, namely planning, preparation and the consequences of this crime, which involved more than one country. Transnational crime is a crime that crosses the boundaries of a country. The scene of the incident, the purpose of the crime and the consequences that arise from the crime are some aspects of transnational crime that do not have a specific territorial boundary. Illegal fishing has been regulated in Indonesian regulations, namely in Law no. 45 of 2009 concerning Fisheries. In addition, this regulation on Illegal Fishing has also become an old issue in the scope of international law which later formed an international legal  framework that prohibits illegal fishing practices, this arrangement is contained in the United Nations Convention on the Law of the Sea or UNCLOS which was ratified in 10 December 1982, and later ratified by Indonesia in Law no. 17 of 1985 on Ratification of the United Nations Convention on The Law of The Sea