He spent a chilly night near Blackfriars Bridge last week with Seyi Obakin, the chief executive of British homeless charity Centrepoint. William has been the charity's patron since 2005.
"I cannot, after one night, even begin to imagine what it must be like to sleep rough on London's streets night after night," William said Tuesday. Poverty, mental illness, drug and alcohol dependency and family breakdown cause people to become and then stay homeless.
"I hope that by deepening my understanding of the issue, I can help do my bit to help the most vulnerable on our streets."
William, second in line to the throne, was exposed to some of the hardships found on London's streets when his mother, Princess Diana, took him to a shelter in 1996. Just 13 at the time, William spent an hour at the facility with his younger brother, Harry.
Diana was well-known for her charitable work and the homeless was a group she was particularly close to. She had also served as Centrepoint's patron, a position she held at the time of her death in 1997.