Exports of goods rose 6% in May compared to the previous month, new data from the Central Statistics Office showed.
In total, goods worth €13.6bn left the country during the month, up from €12.8bn in April.
Overall, the value of goods exports for the period January to May was €66bn, a decrease of €2.1bn or -3% when compared with the first five months of last year.
The continued strong performance in May was driven by shipments of professional, scientific and controlling apparatus, which rose 41% to €555m when compared to the same month last year.
Exports of electrical machinery, appliances and parts increased by 34% to just over €1bn.
But after strong performances earlier in the year, exports of medical and pharmaceutical products decreased by €923 million or -17% to €4.4bn.
Exports to Great Britain were up 28% to €1.2bn, with the largest growth seen in machinery and transport equipment and food and live animals.
However, imports from there decreased 24% compared to May of last year.
Food and live animals and machinery and transport equipment accounted for much of the reduction in imports.
Overall, total imports increased by €2.2bn or 36% in May 2021 compared with May of last year.
Imports of electrical machinery, apparatus and appliances increased by 177% to €716 million, while imports of organic chemicals were up by 34%.
"This decrease has been triggered by a notable weakening in the food and drink trade from Great Britain to Ireland since the start of the year, given the increased customs controls, checks and costs on bringing such products into Ireland," said Jarlath O'Keefe, Partner in Indirect Taxes at Grant Thornton Ireland.
"Notwithstanding the decline in imports, the UK market remains an important player in Ireland's export market and this is evidenced by the fact that exports to Great Britain increased by 28% in May 2021 compared to May 2020."
"However, the previous over-reliance on the British market is no longer the case, given that exports to Great Britain accounted for 9% of overall exports from Ireland which demonstrates that the Irish market is continually sourcing new markets for its products, which has been made possible due to the recent surge in e-commerce related business transactions."