Vizeum won the account in a final shoot out with Omnicom's Rocket and WPP’s Mindshare.
Mindshare was not on the original shortlist but was invited by Carnival Group to vie for the business at the final stages of the pitch.
Carat and incumbent Starcom were knocked out of the running at an earlier stage.
The process, handled by Fairbrother Lenz Eley and led by Philip Price, head of brand marketing at P&O Cruises, was part of a wider review of all Carnival suppliers.
Last month Carnival Group Cruises reappointed Miles Calcraft Briginshaw Duffy to handle its £7 million P&O Cruises creative account after a pitch against The Red Brick Road, TBWA\London and Adam & Eve, handled through the AAR.
