Samuel Davies was last seen in the Sea Street area at around 3.15pm on Wednesday 6 October 2021.
The 16-year-old is described as being white, five feet and nine inches tall and of slim build with short, brown hair.
When he was last seen, Samuel was wearing a black jacket, black jeans and dark walking boots. He was also carrying a black rucksack.
Officers are concerned for his welfare and anyone who sees him or knows where he might be is urged to contact Kent Police on 999 quoting reference number 6-1220.