It is expected to meet surging demand arising from closer economic ties between the two former rivals.
"The cable received the approval of National Communications Commission on November 1," Chen Jung-kuei, an official of Taiwan's leading telecom operator Chunghwa Telecom, told AFP, referring to the island's telecom regulator.
Chinese authorities have also given the go-ahead for the fibre-optic undersea cable, he said.
"With the opening of the cable, the quality of communications service across the (Taiwan) Strait will be enhanced," Chen added.
Currently, telecommunications between Taiwan and the mainland are routed indirectly through countries such as Japan.
Chunghwa Telecom, Taiwan's leading telecom operator, and three other local telecom operators jointly hold a 50 percent stake in the Tw$1 billion (USD 34 million) project, while two Chinese firms share the remainder.
Telecoms demand between Taiwan and China has risen sharply recently, driven mostly by a corporate demand for greater data capacity.
Another Chunghwa official said audio is expected to account for no more than two percent of the cable's bandwidth.
Demand is expected to surge further in the years ahead as Chinese operators press for fourth-generation mobile communications.
The undersea cable project comes amid fast-warming ties between Taiwan and China under Beijing-friendly President Ma Ying-jeou, who took office in May 2008 on promises to boost cross-strait economic ties.
