International transport service trade can be divided into two categories: international freight transport service trade and international passenger transport service trade. However, international transportation service is a contractual relationship, whether it is cargo transportation or passenger transportation. One party to a contract is the consignor or passenger of the goods, and the other party to the contract is the carrier (ship company, railway transport company, airline company, etc.). The basic right and obligation relationship stipulated in the international transport service contract is that the carrier carries the cargo of the passenger or the shipper to the agreed place within the agreed period (the carrier also delivers the goods to a particular consignee in the transport of the goods); the passenger or the shipper will pay the agreed cost to the carrier in the agreed manner.
The international trade in transport services can be adjusted by international treaties and international conventions in addition to the adjustment of the domestic law of the relevant countries (such as contract law, maritime law, etc.) and the case law of the relevant countries.