Topping the chart for the second year in a row and third year in total, the singer-songwriter finished ahead of Calvin Harris in second and Little Mix in third.
His last official single release in the UK was the multiplatinum-selling Perfect, the 2017 Christmas number one.
Sheeran, famous for hits including Shape Of You, Photograph and Sing, has held the top spot in three of the last four years - 2015, 2017 and 2018 - and has been in the top five most-played artists five times since his first album + was released in 2011.
The chart is compiled by music licensing company PPL, which counts each play an artist receives from broadcasters and in public places such as pubs and shops.
Nine of the top 10 most-played artists of 2018 were British, with George Ezra and Coldplay - who also had a break from releasing music in 2018 - all making the list.
P!nk is the only non-UK artist featured.
Meanwhile, the most-played song in 2018 was Feel It Still by Portugal The Man - originally released in 2017 - according to PPL.
These Days by Rudimental, featuring Jess Glynne, Macklemore and Dan Caplen, came in second, while Liam Payne and Rita Ora's For You (Fifty Shades Freed), One Kiss by Calvin Harris and Dua Lipa, and George Ezra's Shotgun completed the top five.
P!nk's What About Us edged in at number 10, making the list for the second year in a row - an achievement only seen once before, by Maroon 5's Moves Like Jagger in 2011 and 2012.
PPL chief executive Peter Leathem said: "Radio, TV and public performance usage is a significant indicator of the most played music in the country, so PPL is pleased to report a successful 2018 for home-grown UK talent."
© Sky News 2019