Archaeological finds and excavations have shown that there was a port and trading centre of the local Sa Huynh people along the Thu Bon River as early as the 2nd century BC. This continued to expand, especially during its most flourishing period from the late 16th to the early 18th centuries. It was through Hoi An that Christianity penetrated Vietnam in the 17th century.
By the end of the century, the rise of other ports on the coast of Vietnam, in particular Da Nang, and silting of its harbour, led to the final eclipse of Hoi An. As a result of this economic stagnation, it has preserved its early appearance in a remarkably intact state, the only town in the country to have done so.