Ireland was previously managing director of Diageo’s East Africa Breweries Ltd arm but is moving to London to head up the UK team.
Cowan, who has been in charge of Diageo GB since 2011, is heading in the opposite direction and will take up Ireland’s old role leafing EABL, reporting to Diageo Africa president John Kennedy.
Both Ireland and Cowan will begin a month of transition to their new roles from July 1.
John Kennedy, president for Diageo’s Europe, Russia and Turkey arm, said: “I would like to thank Charles and Andrew for the significant impact they have made on EABL and GB respectively. Charles has transformed EABL to be one of the best performing markets in Diageo and the fastest growing market for Guinness.
“Over the last few years, under Andrew’s leadership, Diageo GB has seen consistent top line growth, profit growth and sprits market share growth, and Guinness is also growing again with increased value share. Both are tremendous achievements and I congratulate them both on their new appointments.”
Ireland has spent the past 13 years heading teams for Diageo in Asia Pacific and Africa.