The 108th joint Mekong River patrol by China, Laos, Myanmar and Thailand concluded on Friday, with three Chinese law-enforcement vessels returning home to a port in southwest China's Yunnan Province.
The three vessels navigated over 500 km over four days and three nights, said the Yunnan provincial public security department.
The patrol targeted cross-border crimes, including illegal immigration, drug smuggling, criminal telecommunications and illegal internet activities in the Mekong River basin.
The Mekong River, known as the Lancang River in China, is a vital waterway for cross-border shipping.
China, Laos, Myanmar and Thailand have been carrying out joint patrols on the Mekong River since December 2011.