A free port refers to a port where all or most foreign goods can enter and exit duty-free outside the customs border of a country. Also known as free ports, free trade zones and foreign trade zones, these ports are located outside a country's customs territory, and foreign goods can be freely modified, processed, stored or sold in the port except for being exempted from customs duties when entering or leaving the port. However, it shall abide by the relevant policies and decrees of the host country. Free ports are divided into complete free ports and limited free ports according to trade control. The former implements duty-free import and export of all commodities, while the latter imposes a small amount of tariffs on a few commodities with certain trade restrictions. Freeport is mainly engaged in entrepot trade. Some free ports and non-free ports are clearly defined, while others are not. Some bonded areas not located in the port area are engaged in processing, tourism, service and other industries besides entrepot trade. Opening a free port can expand entrepot trade, obtain various trade expenses and increase foreign exchange income. Hong Kong is in such a system, so it is said that Hong Kong is a free port.