The shop will work on Royal Caribbean’s overall strategy to support its growth in the UK. It will also handle creative activity, direct and digital marketing in the UK.
J Walter Thompson London is the incumbent for the UK arm of Royal Caribbean and did not repitch.
Jo Briody, the director of marketing and PR at Royal Caribbean International, said: "TBWA\London very quickly got to the core of our business.
"They showed a deep understanding of our challenges and opportunities, successfully marrying clever strategic thinking with great chemistry with our team at every stage."
The company called the review in February. Creativebrief handled the process.
Richard Stainer, the chief executive at TBWA\London, said: "Royal Caribbean International is an extraordinary, innovative brand.
"We're delighted to be their choice of partner as they look to disrupt the cruising market more than ever."
J Walter Thompson New York holds the global account.