Thailand's international reserves fell to $275.5 billion in July, according to data released by the Bank of Thailand (BOT) on Friday.
The reading compares with the $279.2 billion recorded in the previous month.
The monthly movement was primarily driven by a fall in foreign currency reserves, which reached $238.09 billion, while the central bank's gold holdings were valued at $30.49 billion. Meanwhile, the country's net forward position stood at $24.73 billion.