RKCR/Y&R won the business after a final shoot-out against JWT. Delaney Lund Knox Warren also pitched for the account, but was eliminated at an earlier stage.
Arena BLM won the media account in a pitch against MediaVest. The previous incumbent on both parts of the business was Bray Leino, which was appointed in 2007.
RKCR/Y&R and Arena BLM will now be responsible for contemporising the Honey Monster character and creating a series of campaigns centring on the brand icon.
The agency's first work for the brand is due to break later this year on TV and other major channels, and will focus on its Honey Waffles variant.
During its time working on the account, Bray Leino was responsible for launching a £3.5m TV campaign that featured the Honey Monster rapping with his flatmate about their mutual love of Sugar Puffs.
The ad saw the return of the brand icon for the first time in five years, and came under fire after the comedians behind The Mighty Boosh accused the ad of ripping-off the "crimping" style used in their TV show.