Blue 449, the media agency previously known as Walker Media, picked up the business following a pitch that also involved the7stars.
Kayak appointed ZenithOptimedia, Blue 449’s sister agency, as its pan-European media agency in 2013 but it has not spent a significant amount of money in the UK since then. It is understood that the brand is now planning a major brand campaign.
Hal Pearson, the vice president, media, Europe at Kayak, said: "Blue 449’s approach was refreshingly open and commercially focussed. They want to drive our business forward first and foremost, and be rewarded for successfully doing so. We’re keen to get started with them."
Kayak is owned by The Priceline Group and allows users to compare prices of hotels, flights and cars from the same portal. Most travel comparison sites do not offer all three types of holiday service.
Simon Davis, the chief executive at Blue 449, said: "Even prior to launching Kayak has already built a sizeable business in the UK, by having an incredible product with unique functionality which users love.
"The marketing team are super smart with a clear perspective on how to make Kayak the category leader in the UK so we’re delighted to be working with them on the launch."
Earlier this week Blue 449 won the media account for David Lloyd Leisure Group.