Maritime traffic reached the farthest areas in the Tang Dynasty.

The farthest sea in the Tang Dynasty was from Guangzhou to East Africa.

Tang Dezong Zhenyuan (785-805 AD) Prime Minister and geographer Jia Dan (730-805 AD).

The article "Guangzhou Tonghai Post Road" records the route from Guangzhou to East Africa. This route starts from Guangzhou, China, passes through the southeast of Hainan Island, along the east coast of Indian zhina Peninsula in the South China Sea, passes through Siam Bay, goes south along Malay Peninsula, reaches the southeast of Sumatra Island, and reaches Java Island. Then go west out of the Straits of Malacca, pass through the Nicobar Islands, cross the Bay of Bengal to Shizi (now Sri Lanka), travel along the west coast of Indian Peninsula, cross the Arabian Sea, pass through the Strait of Hormuz to the head of the Persian Gulf near Abadan, go back to the Euphrates River to Basra, and then travel thousands of miles to the northwest Arab capital Baghdad (on the Tigris River). From the Persian Gulf to the Strait of Hormuz, sail westward along the south bank of Arabian Peninsula, pass through Bahrain, Oman and Yemen to the Mande Strait in Hongkou, and go south to East Africa along the coast.

Jia Dan records that this route took more than 90 days from Guangzhou to Basra. It takes 48 days to sail west from Basra to Dar es Salaam, Tanzania, East Africa. Ocean-going ships in the Tang Dynasty were able to sail in the waters of the western Pacific Ocean and the northern Indian Ocean, which shows the ocean-going navigation ability of the Tang Dynasty. In the Tang Dynasty, ivory, rhinoceros horn pearls, precious stones, corals, colored glasses, frankincense, Long Xianxiang and other spices and tortoise shells were bought and exported to China, while China's silk porcelain, tea and ironware were also exported to Asian and African countries. Overseas trade is unprecedented.