The pair's campaign, titled "Whose side are you on," looks to fight illegal trade of wildlife products and raise awareness of conservation issues around the world.
While speaking at Google Town Hall in London, the Duke of Cambridge, who presides over the organization, and Beckham, a new ambassador for UFW, spoke about the dangers of illegal hunting.
"Illegal wildlife trade thrives because it is hidden, often invisible, making it easy for criminals," said the royal.
"It's devastating. It really is devastating," added Beckham. "And we're in a world where our generation, and the younger generation can really, really make a difference and we really need to do it now."
"Are we on side of the criminals? Or are we on the side of the animals?" Beckham continued. "I know what side we're all on and I'm sure you know what side you're all on."