In 1947 he went to University College, Galway, on scholarship, took courses in Celtic Studies, archaeology, history and the classical languages, and graduated with an M.A. in 1953.
In 1947 he went to University College, Galway on scholarship. After taking courses in Celtic Studies, archaeology, history and the classical languages, Mac Eoin was awarded a B.A. with first-class honours in 1951 and an M.A. in 1953.