The waivers are part of a US$10-billion stimulus package to boost growth, including a debt moratorium for farmers, loans for smaller businesses, and more money for low-income earners.
"The cabinet approved the extension of fee waivers until April 2020," Prime Minister Prayuth Chan-ocha told reporters, adding that the scheme would cover Lunar New Year and the Thai new year, Songkran.
Foreign tourist receipts make up about 12% of Southeast Asia's second largest economy, but arrivals increased just 0.89% in June, with visitors from China, the biggest source, declining 7.1% from a year earlier.
The fee of THB2,000 (US$65) is to be waived unil next year for travellers from 18 countries, including China and India.