Abstract   South Korea has started cracking down on Chinese vessels in the Yellow Sea, in response to their increasing illegal fishing activities and armed resistance. This research examines changes in Korea's use of force against Chinese illegal fishing after exploring the current fishing situation in this undelimited area. Korea's strengthened stance against illegal fishing, as illustrated by its amended Maritime Security Act and the Korea Coast Guard's new internal rules, is studied to verify whether it meets the requirements of international law. Korea's law and practice, in general, seem to respect international law by balancing two purposes: ensuring the effective exercise of law enforcement and the safety of officers and fishermen. This article suggests some recommendations to improve Korea's compliance with international law.