The figure was in line with a flash estimate released by the state-run Statistics Poland (GUS) agency at the end of last month.
In August, the prices of consumer goods and services in Poland were also 2.9 percent higher than in the same month a year earlier, according to Statistics Poland.
In July, Poland's consumer price index stood at 3.1 percent.
Next year, Polish inflation is expected to average 3.1 percent, under the country's budget adopted by the government in August.
The Polish central bank predicted in its latest Inflation Report, released in July, that inflation would average 3.9 percent in 2025, followed by 3.1 percent in 2026 and 2.4 percent in 2027.
(gs)
Source: IAR, PAP