The paper will address the conflict and cooperation between two aspects of private Chinese maritime trade on the coasts and inland rivers of Guangdong and Guangxi provinces: customs clearance and the registration of steamships under the treaty port and modern maritime customs systems; and vague regulations and flexible business models for Chinese junks and steam launches under the triple maritime zones (foreign colonies, treaty ports and non-treaty ports) and dual maritime customs system (foreign customs, native customs and likin administration). Foreign merchants enjoyed the privilege of transit passes that exempted them from further charges when transporting goods to inland China. However, the local Chinese authorities used every means to stop the efficient practice of transit passes in inland China to protect their interests of likin tax income from any ‘Chinese’ vessels and products. Chinese merchants made careful calculations of minimum taxation rates and chose either ‘Chinese’ or ‘foreign’ status accordingly. They borrowed ‘foreign’ status by obtaining foreign registration and a foreign origin for their vessels and cargoes respectively by either paying commission to foreign subjects to gain legal foreign registration papers or by adopting a trade route between the foreign colony of Hong Kong and non-treaty ports in Guangdong and Guangxi provinces. This paper will discuss the trade routes and business models of Chinese junks and steam launches across the porous Hong Kong–China border and the network of treaty and non-treaty ports on the Pearl and West Rivers in the late Qing and early Republican periods.