Mel Greig and Michael Christian, of Sydney station 2Day FM, duped staff at the King Edward VII's Hospital in London by pretending to be members of Britain's royal family to gain information about Catherine's condition while she was being treated for severe morning sickness.
The nurse who took the call, Jacintha Saldanha, was found dead three days later in a suspected suicide, prompting a probe into the incident.
However, British authorities have now confirmed the two DJs will not face criminal prosecution over the call as there is not enough evidence to support a manslaughter charge.
Officials at the U.K.'s Crown Prosecution Service (CPS) have revealed there is evidence to warrant further investigation of other less serious offences, but that will not go ahead because they couldn't support the DJs' extradition from Australia on more minor offences.
Malcolm McHaffie, deputy head of special crime at the CPS, says, ""It is not possible to extradite individuals from Australia in respect of the potential offences in question. However misguided, the telephone call was intended as a harmless prank. The consequences in this case were very sad. We send our sincere condolences to Jacintha Saldanha's family.""
The news comes just days after Greig and Christian's Hot 30 radio show was officially axed by bosses at 2Day FM. The show was taken off air in the aftermath of the prank, and the hosts have yet to return to the airwaves.