This article traces the Chinese accommodation of foreigners in the lower section of the Pearl River delta during the Opium War to the region’s social ecology in late imperial times. With a long tradition of living with foreign sojourners and their vessels, Chinese people in the delta congregated on an unprecedented scale at the outer anchorages within the present-day Hong Kong region in 1839–1841 to trade with Euro-American merchants and the British expedition. As mobile and violent provisioners and opium dealers, they flourished in the littoral borderland between the Qing and British empires. Their cross-shore ventures constituted an intensification of their prewar activities and an economic adaptive strategy in the competitive society of mid-Qing Guangdong. Centering on the socioeconomic lives of ordinary Chinese people, this article problematizes the usage of “Hanjian” and “collaboration” as nationalist and statist labels to summarize Chinese assistance to foreigners in times of external war in modern China.