This article undertakes a comprehensive legal assessment of Chinese maritime militia vessels and their operations, employing a law enforcement perspective as the analytical lens. During peacetime, those vessels engage in fishing and low-intensity military activities but during armed conflict they transition to tasks like reconnaissance. Notably, these maritime militias are frequently deployed in what is commonly termed as "gray zone" scenarios, which lack a clearly defined designation as either peacetime or armed conflict. Their principal objective lies in asserting territorial claims without resorting to full-scale armed conflict. This article delves into an exploration of the legal status accorded to these vessels, examining whether they are entitled to the sovereign immunity afforded to warships and ships operated by a State for non-commercial purposes under international law. Additionally, it scrutinizes the question of whether maritime militias and their activities are subject to functional immunity (ratione materiae) under international law. It embarks on an investigation into the permissible law enforcement measures that a coastal State can undertake against these vessels within its various maritime zones. Additionally, it explores potential avenues through which a third State might exercise jurisdiction in collaboration with the coastal State, should the need arise.