The agency was set up last year by Robin Dhara, former account manager at Euro RSCG Biss Lancaster, and comms officer at Euro RSCG UK Group.
Sonim Technologies created the JCB Toughphone - a phone that can cope with being smashed with a hammer - last year.
Red Robin has been hired to help launch a follow-up phone designed to withstand being submerged underwater.
Red Robin will handle UK and pan-European PR on a retainer basis while Porter Novelli will be handling the corporate PR for Sonim in the US.