The 23-year-old was previously on the books at West Ham United for two-and-a-half years, but did not play a senior first-team game for the Hammers.
He is the League of Ireland Premier Division's top scorer so far in the 2017 season, with 16 goals.
Maguire has been with Cork - the league leaders - since December 2015.
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Preston North End have signed Cork City striker Sean Maguire on a three-year contract from the end of July for an undisclosed compensation fee.