<![CDATA[Criminal immigration violations have become an urgent legal issue due to the increasing mobility of foreign nationals entering Indonesia through Kupang, a strategic border gateway between Indonesia and Timor Leste. This study aims to analyze the supervision and criminal law enforcement carried out by the Class I TPI Immigration Office of Kupang and evaluate whether such measures create a deterrent effect. This research employs an empirical juridical method with a socio-legal approach using interviews with immigration officials and official immigration violation data from 2024–2025. The findings show that 77 violations occurred in 2024 and 67 in 2025, mostly involving nationals from Bangladesh, Myanmar, and China. Many cases fulfilled the elements of criminal offenses under Article 113, Article 119 paragraph (1), and Article 122 letter a of Law Number 6 of 2011 on Immigration. However, all 144 cases were resolved through administrative measures, namely detention and deportation, without criminal prosecution. This indicates that immigration criminal law tends to function as dead letter law and reflects a gap between law in books and law in action. Administrative dominance is influenced by limited certified investigators, coordination constraints with the Prosecutor’s Office, and efficiency considerations. The study concludes that immigration criminal law enforcement in Kupang remains ineffective and recommends strengthening investigator capacity, institutional coordination, and selective criminal enforcement for repeated and organized violations.]]>
