Some 2.8 million people from the Chinese mainland, Hong Kong and Macau visited Taiwan in the first half of 2015.
The number accounted for 55 percent of the nearly five million visitors to the island from January to June, Xinhua reported.
The mainland was the biggest contributor of visitors to Taiwan in the six months. Japanese and South Koreans ranked second and third, with about 750,000 and 330,000 visitors respectively.
According to Taiwanese authorities, 70.9 percent of the travellers came to the island for sightseeing, 7.7 percent for business and four percent to visit family.
The number of tourists increased by 1.4 percent, or 49,538 people, as compared to the same period last year.
A total of 3.95 million mainland visitors came to Taiwan in 2014, an increase of 38.6 percent year-on-year.