The 74th joint patrol on the Mekong River by law enforcement from China, Laos, Myanmar and Thailand began on September 18.
Three Chinese vessels participated in the mission, which was aimed at reducing crime in the region.
Targeting drug trafficking along the Mekong River, the patrols conducted random inspections of ships in waters near key regions including the Golden Triangle.
The joint patrols started in December 2011 after a gang hijacked two cargo ships and killed 13 Chinese sailors in Thai waters on October 5, 2011.
The Mekong River, known as the Lancang River in China, runs through China, Laos, Myanmar, Thailand, Cambodia and Vietnam and remains an important waterway for transnational shipping.