Mehdi Aitsilarbi, 16 and Destiny Ema, 13, were last seen around 8pm on Saturday, August 19 in the Square Lane area.
Mehdi is described by officers as white, 5ft 9in tall, of slim build with dreadlock-style hair. At the time of his disappearance he was wearing a black jacket, dark blue Puma tracksuit and white Nike trainers.
Destiny is described as black, 5ft 8in tall, of slim build with a short, afro-style haircut. He was wearing a white t-shirt, red jogging pants and red Nike trainers at the time of his disappearance.
Police have said they are concerned for the pair’s welfare and are urging anyone with information to contact officers.
PC Mike Cobley, of Preston Police, said: “Mehdi and Destiny have been missing for several days now and we are appealing for information leading to their whereabouts.
“If you have seen them, or know where they are, please contact police.
“Furthermore, I would urge Mehdi and Destiny, if they see this appeal, to come forward and let police know they are safe and well.”
Anyone with information can contact police on 101 quoting log references 1418 and 1488 of August 19.