The agency was appointed following a review of the business that began in June and was handled by Creativebrief.
It is the first time the cruise company has appointed a standalone social media agency, with previous work split between its existing shops.
The Royal Caribbean’s $90 million global advertising account is handled by a WPP group comprising JWT and Mindshare, based in New York. The team has handled the business since 2007, after it won the account from Arnold Worldwide.
JWT London handles Royal Caribbean’s creative work in the UK, after winning the business following a competitive pitch involving VCCP Blue and Isobel in 2012. It is the second travel-related win in 2014 for Holler.
The agency picked the global account for youth travel firm Contiki Holidays earlier this year.