The Red Brick Road beat The Gate and M&C Saatchi to the business.
The pitch was managed in-house by the client and will cover sister sites Schlaubi.de in Germany and Comparaiso.es in Spain.
Mark Irwin, the marketing director of Broadbandchoices.co.uk, said: "We are very excited by the prospect of developing our advertising creative concept with the team at The Red Brick Road.
"All of the agencies who pitched demonstrated compelling ideas, but TRBR particularly stood out with their excellent approach to this project, their clear insight-driven ideas and great execution."
Broadbandchoices.co.uk is an Ofcom-accredited comparison service for TV, mobile phone, broadband and home-phone services.
David Miller, the managing director at The Red Brick Road said: "The communications and entertainment sector is incredibly dynamic, and needs a consumer champion who can give genuinely independent advice."