Inflation rises to 3.9% in September as energy costs push prices higher

Impact of volatile global energy market 'laid bare' by the latest inflation figures

The rate of inflation increased to 3.9% in September, driven by rising energy prices, data published by the CSO on Thursday shows.

The rate of inflation increased to 3.9% in September, driven by rising energy prices, data published by the CSO on Thursday shows.

The EU Harmonised Index of Consumer Prices (HICP) for Ireland - a measure of price inflation - is estimated to have increased by 3.9% in the 12 months to September 2026 and risen by 0.2% since August. This compares with HICP inflation of 3.4% in Ireland in the 12 months to August.

The data shows energy prices are estimated to have increased by 2.9% in September alone and have gone up by 15.3% year on year.

Food prices are estimated to have remained unchanged in the last month and grown by 0.3% in the last 12 months. Excluding energy and unprocessed food, the HICP is estimated to have risen by 2.8% since September 2025.

Deloitte Ireland chief economist Kate English said the impact of the volatile global energy market has been "laid bare" by the latest inflation figures. "As we head into winter, there will be greater energy demand, so it is difficult to see energy costs doing anything other than remaining elevated. Energy prices have risen in this country by 2.9% in the last month alone, reflecting higher prices in energy markets, namely oil, that had dissipated somewhat over the summer.

“While food prices remained unchanged in the last month, there is a lag between fuel price increases and subsequent food price increases of typically eight to 10 months, based on Central Bank of Ireland estimates. Energy prices rose significantly back in March, which means that the second-round effects (in the form of higher food prices) may begin to rear their heads from late October onwards.

“Inflation seems to be here to stay and that will have a negative impact on individuals, households and businesses."