"It is a historic day... We will have enough vaccine to develop herd immunity," said Prime Minister Prayut Chan-o-cha, as reported by the news agency AA.
The 200,000 doses, the first shipment among 2 million doses Thailand ordered from the Chinese biopharmaceutical firm, were delivered by a Thai Airways International cargo flight from Beijing to Bangkok.
The first batch of the Sinovac vaccines will be distributed to 13 provinces, including Bangkok, and administered to at-risk groups, including medical workers, close contacts with COVID-19 patients and people with certain chronic illnesses.
The second batch of 800,000 doses of the Sinovac vaccines is scheduled to arrive in Thailand next month, followed by a third batch of the remaining 1 million doses.
Thailand has set a three-staged national inoculation program, aiming to vaccinate enough of the general population to create herd immunity. Besides the Sinovac vaccines, it would also use AstraZeneca vaccines.
As of Wednesday, the Southeast Asian nation's total COVID-19 tally rose to 25,692, with more than four-fifths of the infections being detected since the new wave of outbreak erupted in the country in mid-December.