Its tourism industry generated more than THB850 billion (US$26.2 billion) in revenue, according to the Ministry of Tourism and Sports.
Malaysia continued to be the largest source of visitors to Thailand with 2.53 million, followed by China, India, Russia and South Korea.
Despite a slight year-on-year decline, local media said the outlook for inbound tourism remains strong, supported by government promotional efforts and seasonal travel demand.
The number of foreign arrivals is expected to rise further in the coming weeks, bolstered by ongoing school holidays in Europe and East Asia, particularly in China and Japan, alongside the rollout of tourism campaigns, Bangkok Post reported.
Concerns over tourist safety in Thailand have grown in recent months, particularly after the kidnapping of Chinese actor Xing Xing in January.
Escalating military clashes along the Thai-Cambodian border have begun to take a toll on Thailand's tourism industry, triggering a surge in accommodation cancellations across provinces near the fighting.
The Australia, Canada, U.K. and U.S. governments have warned their citizens to exercise caution while traveling to Thailand and Cambodia after border clashes.