Thailand has logged more than 50,000 international arrivals so far since fully reopening the country for tourism at the beginning of November.
Government data recorded the 50,000 international travellers in the first three weeks.
It took the total number of foreign arrivals so far in 2021 to 100,000.
Top source markets are the US, UAE and Germany.
Officials are now predicting about 200,000 by the year-end.
Fiscal Policy Office director Pornchai Thiraveja said the target next year is up to six million foreign tourists or even seven million if China allows outbound travel in 2022.
Thailand started the "Test and Go" programme on 1 November for travellers from more than 60 countries.
It requires a one night quarantine hotel stay pending a negative PCR test result.
Before the pandemic, Thailand welcomed 38 million foreign arrivals.
