Bank of Ireland made a pre-tax profit of just over €1.1bn (£930m) in the first half of 2023, up 5% on the same period last year.
It has been helped by the strong performance of the Irish economy where it generates 75% of its profits.
Its UK retail division, which includes its Northern Ireland business, saw its profit increase from £117m to £167m.
The bank said lending by the UK business has started to increase after a period where it had fallen due to refocusing of its operations.
It is pursuing a “value rather than volume”, strategy in the UK, targeting only more profitable lending opportunities, particularly in mortgages.
As part of that, it has ended a financial services partnership with the AA in the UK.
The bank’s chief executive Myles O’Grady said overall performance in the first half of the year had been “excellent”.
“We are entering the second half of the year with momentum notwithstanding geopolitical developments and the evolving competitive environment,” he said.
“We have now reached the mid-point of our three-year strategic cycle and are meeting or beating all the targets we have set.”
Bank of Ireland also benefits from a relatively uncompetitive retail banking market which is dominated by it and its main rival AIB.
However, the market is set to become more competitive with the Spanish lender Bankinter intending to expand its operations in the country and Revolut planning to offer mortgage lending next year.