The agency won the brief after going head to head with Dentsu Media Palette in the final round of pitches.
The incumbent, OMD, the agency that Pepsi is globally aligned to, was eliminated from the running at an earlier stage of the pitch.
Thailand is one of very few countries where Pepsi has a higher market share than Coca-Cola. The drink pulls in more than 60 per cent of the market share.
Pepsi called a review of its media account in July, as part of a regular series of reviews by the company.