A series of three ads, launched in November, aimed to visualise the idea of a lost generation.
The campaign was devised and created pro bono by CHI & Partners, with Clear Channel donating the ad space and Communisis printing the ads free of charge.
Young people who had been previously helped by the charity were painted by hand to create the effect of being blended into urban backdrops.
British body painter Emma Cammack spent more than 24-hours on location to create the effect.
Dan Farmer, acting head of marketing at The Prince's Trust, said: "Our new campaign paints a very bleak picture of a generation at risk.
"The Trust wanted to use its 'Lost Generation' campaign to capture the general public's imagination and position the charity as a real option for young people – giving hope to too many in need of support."
One of the young men used in the campaign is 25-year-old Jarred King from Mitcham. He was painted from head to foot to blend into a Southwark stairwell.
King said: "The Prince's Trust helped me to set up my own business, so it's a real privilege to help spread the word about its work.
"I grew up in an area where a lot of young people were out of work and had lost their way in life, but l bucked the trend with help from The Trust. The charity is there for a generation affected by very worrying levels of unemployment and I'm proud to be a part of it."
Other backdrops for the advertisements included tower blocks in Kennington Park and an estate in Loughborough.
CHI started working with The Prince's Trust in 2005. The agency is part of a network of ongoing charitable partnerships with the trust.
More than 7,000 six-sheet ads have appeared at bus stops around the UK.