Cian was seen at Wolfe Tone Square Middle, Bray, Co. Wicklow on Friday night, November 25 at approximately 11.10pm.
He is described as being 5’9″ in height, of medium build with short blonde hair and brown eyes.
When last seen, Cian was wearing black tracksuit, a grey hoodie with a fur collar and white trainers.
Anyone with information on Cian is asked to contact them at Bray Garda Station on 01 6665300.