Thailand's headline consumer price index (CPI) rose 0.3% in September from a year earlier, slowing from a 0.88% year-on-year increase in the previous month, the Commerce Ministry said on Thursday.
The figure compared with a forecast rise of 0.8% for September in a Reuters poll. The core CPI was up 0.63% year-on-year in September.
Inflation in September slowed due to lower energy prices from government support measures and a decline in food prices, the Commerce Ministry said, adding inflation would slow on a quarter-on-quarter basis.
Thai inflation has been below the Bank of Thailand's (BoT) target of 1% to 3% for the fifth consecutive month.
In the first nine months of the year, headline inflation rose at an average of 1.82% and core inflation rose 1.5% from the same period a year earlier.
BoT governor Sethaput Suthiwartnarueput said on Wednesday that Thailand's economic recovery is intact but inflation risks could weigh on the country's growth outlook.