I Indonesia, as the largest archipelagic country in the world, has a vast exclusive economic zone (eez) and is rich in fishery resources. however, this also makes indonesia\\\'s eez vulnerable to illegal, unreported, and unregulated (iuu) fishing practices by foreign vessels. this study examines whether the iuu fishing practices by the run zeng 03 and 05 vessels have violated the provisions of unclos 1982, and whether law enforcement by indonesia is in accordance with the convention. the method used is normative juridical with descriptive research and qualitative analysis. based on the results of the study, the iuu fishing practices by the two vessels are considered illegal and unreported fishing because they were carried out without permission from indonesian authorities and without reporting the catch. in addition, both vessels were proven to have violated the provisions of unclos 1982, especially articles 56, 58, 61, 62, 73, 192, and 193. indonesia has implemented law enforcement through arrest, inclusion, and legal download based on the authority of the coastal state. however, the prison sentence against the captain of the run zeng 03 ship by the tual district court was deemed inconsistent with article 73 paragraph (3) of unclos 1982 which does not permit corporal punishment for fisheries violations in the eez. this conclusion emphasizes the importance of harmonization between national law and international obligations to maintain compliance with international maritime law.