Dressed in smart suits and ties, the royal Highnesses were filmed at Charles' London home, Clarence House, and spoke about the devastating effects of the trade.
"We have come together, as father and son, to lend our voices to the growing global effort to combat the illegal wildlife trade," said Charles.
"A trade that has reached such unprecedented levels of killing and related violence that it now poses a grave threat not only to the survival of some of the world's most treasured species, but also to economic and political stability in many areas around the world."
The Duke of Cambridge, who has been patron of conservation charity Tusk Trust since 2005, then went on to speak about the responsibilities of his generation.
"Despite the terrible crisis that we now face, we both continue to be optimistic that the tide can be reversed," said William. "We have to be the generation that stopped the illegal wildlife trade, and secured the future of these magnificent animals and their habitats, for if we fail, it will be too late."
The nine-minute clip ended with Charles and William saying the phrase "Let's unite for wildlife!" in Arabic, Vietnamese, Swahili, Spanish and Mandarin, in order to be understood by as many people as possible living in the countries most affected by the illegal wildlife trade.
The Prince and Duke have a number of engagements planned for the week to raise awareness about the plight of endangered animals.
On 12 February, William will attend the United for Wildlife Symposium at the Zoological Society of London, followed by a reception at the National History Museum to mark the start of London Conference on the Illegal Wildlife Trade.
The following day, both Charles and William will attend the conference, when the first-in-line to the throne will deliver a speech. The event aims to discuss the issue of combating the illegal wildlife trade and agreeing on a more coordinated global response to help eradicate it.
As a keen campaigner for wildlife preservation, Charles became president of WWF UK in 2011. Much like his father, William assembled and became president of United for Wildlife, a collaboration of seven global conservation organisations.