Initially available in the Apple store for iOS, it will shortly be introduced for Android devices as well through Google Play.
The new app offers "all the benefits of Radioplayer's online platform, but on the move", it is claimed.
Features include a 'station scroller', a powerful search engine to access live and catch-up radio, and the ability for users to set up their favourite stations, browse radio that's local or trending, and share listening via social media.
Andrew Harrison, Radioplayer's chairman, says: "This new app will help smartphone users to discover the depth and breadth of UK radio."
A not-for-profit company founded by the BBC, Global Radio, Guardian Media Group, Absolute Radio and RadioCentre, Radioplayer has been dubbed both the Freeview and iPlayer of radio.
The online hub offers 150 BBC and commercial radio stations, plus another 150 local and community stations.
In a separate development, the BBC is believed to be developing a new 'iPlayer for music' that will deliver a service similar to Spotify.