The figure represents a 2.46-per-cent year-on-year increase.
Total spending among foreign tourists last month was down 3.6 per cent, to Bt188.8 billion, the ministry said.
There were 2.39 million arrivals from East Asia, up 3.55 per cent, and they spent Bt97.46 billion, down 2.26 per cent.
The number of visitors from other Southeast Asian countries grew by 12.25 per cent to 836,788, with total spending of Bt25.47 billion, up 11.14 per cent.
Some 1.03 million Chinese visited, down 3.71 per cent, with spending of Bt49.38 billion, down nearly 10 per cent.
Arrivals from Europe rose 3.4 per cent to 916,493, spending Bt61.96 billion, down 2.65 per cent.
Arrivals from North and South America dipped 3.3 per cent to 166,321, with spending of Bt10.85 billion, down 9.31 per cent.