A total of 863,540 people from outside Taiwan visited the island in August, down 3.4 percent from the same period last year, according to the island's tourism bureau on Tuesday.
The decline was due largely to plummeting numbers of visitors from the Chinese mainland, though visitors from Japan and the Republic of Korea increased by more than 30 percent to 187,000 and 78,000 respectively.
The number of August visitors from the Chinese mainland decreased 32.4 percent from last year to 248,538. About 190,000 of the visitors were tourists, against 296,000 last year.
The number of mainland visitors, which rose to about 4.2 million last year, has declined markedly since Tsai Ing-wen took office. Local observers attributed this to Tsai's refusal to recognize the 1992 Consensus, which includes the one-China policy. Her attitude has left mainlanders feeling both puzzled and unwelcome.
The situation has worried many on the island who were employed in hospitality and tourism.
Around 10,000 people from the sector, including the island's hotel, travel agent and tour bus associations, took to the streets in downtown Taipei on Sept. 12, in the sector's first ever demonstration, demanding help for the ailing industry, according to organizers.