OMD will work on tailored social media and SEO campaigns to promote RCL Cruise's three cruise lines – Celebrity Cruises, Azamara Club Cruises and Royal Caribbean.
OMD was appointed after a pitch against a number of undisclosed specialist digital agencies at the end of March. The incumbent was Leeds-based Bloom.
A spokeswoman for OMD said the combined appointment for SEO and social media reflects the growing demand among clients the two services to be integrated.
RCL Cruise's media account is handled by the independent agency AMS. JWT was appointed to the creative account for the Royal Caribbean International in January.
Jo Briody, head of marketing for Royal Caribbean International, Celebrity Cruises and Azamara Club Cruises, said: "Both SEO and social media are central to building awareness of our brands amongst UK consumers and attracting a new to cruise market.
"We are delighted to be working with OMD and are confident they will ensure that our brands are front of mind in the digital arena."
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