Applegreen revenues fell by almost 27% in the first half of the year as the forecourt retailer recorded a €25.5m loss.
Group revenue up to the end of June was €1.1bn, reflecting a sales reduction of 26.6% from the impact of Covid-19 lockdown restrictions.
The loss was in contrast to a €7.4 million profit the company recorded in the first half of 2019.
"Encouragingly, there was a strong recovery in volumes after the initial lockdown in April and this positive momentum has carried into Q3," the company's financial statement said.
"Our balance sheet has recovered strongly from the initial impact of Covid-19 giving us ample liquidity and asset strength to allow the business to continue to deliver on its strategic ambitions.
Applegreen said it has also continued to expand with 559 sites in operation at the end of June across Ireland, the UK and the US.
"We saw a sudden and significant impact on the business from mid-March, particularly in our motorway service areas," CEO Bob Etchingham said.
"This was most pronounced in April and May, but volumes recovered well by the end of the second quarter. To help mitigate some of this impact, the Group took swift and decisive action in managing our cost base and tailoring our retail offer for changing consumer needs."