Ireland played their inaugural One Day International on 13 June 2006. against England which England won the 38 runs, completing the victory in front of a full crowd at Stormont. Mooney took three wickets in the match – those of Marcus Trescothick, Paul Collingwood, and Ian Bell – and later identified the match as one of the highlights of his career. He finished with 30  not out from 26 balls. Mooney was part of Ireland's 15-man squad that travelled to the West Indies in February 2007 to play in the country's first World Cup. They achieved a tie against Zimbabwe and victories over Pakistan and Bangladesh, and ended the tournament ranked 10th overall in the official ICC rankings, taking many by surprise and receiving a "heroes welcome" when they returned home. Ireland were a mostly amateur outfit at the time. After the World Cup, Mooney withdrew from the team in order to complete his electrical apprenticeship.