[6] He enjoys a wide range of music, especially classical and jazz and he listens to Radio 3,[citation needed] but he does not like the sound produced by harpsichords.

[5] Coles was a professor of theoretical astrophysics at Cardiff University from 2007 to 2013, and was the deputy head of the school of physics and astronomy.

[4] He left the University of Sussex in 2016 to return to Cardiff to hold a joint position with the school of physics and astronomy and the Data Innovation Research Institute.

[10] He was a Fellow of the Royal Astronomical Society and of the Institute of Physics,[11] but resigned from both in 2024 due to their use of high article processing charges for their gold open access journals.

He also researches cosmological models that feature magnetic fields, Non-Gaussianity and asymmetries,[5] as well as the application of probability and statistics in astronomy and physics.

[4] Along with Francesco Lucchin he wrote a textbook on "Cosmology: the origin and evolution of cosmic structure" (ISBN 978-0-471-48909-2), and a second edition of it was published by John Wiley & Sons in July 2002.