Sonim Technologies has asked the agency to handle its UK and pan-European PR on a retained basis.
Red Robin's first major project will be to launch the Sonim XP3 Enduro, a waterproof mobile phone built for those who work or play near water.
The agency will work alongside CreativeFeed, which leads Sonim's global digital marketing and creative initiatives.
Red Robin was set up by former Euro RSCG Biss Lancaster account manager Robin Dhara last year.
Porter Novelli handles the corporate PR for Sonim in the US.