He has published three books. Thames Way, a collection of haiku poems, was their first book, released in 2015. This was followed by a second haiku collection, A Thousand Sparks, published in 2018. In 2021, their third book—and first complete poetry collection—The Singing Hollow was released. All three works were published by Alba Publishing (http://www.albapublishing.com).

Diarmuid's poems have appeared in respected literary journals such as The Stinging Fly, Cyphers, and Crannóg. They have also published short stories and received recognition through awards, including the South Dublin Library Poetry Award and arts grants. A professional member of the Irish Writers Centre, they also write nonfiction and works on spirituality.