Owners Bauer Media confirmed the move away from the local DAB network, which boosts the audience coverage by 21% to 85% of the UK.
Managing Director at Bauer Media Steve Parkinson said: "Kiss has seen significant growth in audience over the last two years across its many touch points and multiplatform offering.
"By being able to transmit nationally across the country, we can realise our next ambition to be the first young targeted station available on DAB right across Britain.
"Whether on analogue or digital, whether through the TV or via an app, we have more ambition yet to come for Kiss, and we look forward to a successful and busy 2013."
Broadcast Sales Director Karen Stacey added: "We are thrilled that Kiss will now be reaching 85% of the population and are excited about the advertising opportunities that we will now be able to offer those wanting to reach the youth market.
"We fully intend to maximise on these in order to drive Kiss's success as we look to cement Kiss's place as the only youth radio station with true national digital coverage."