The use of robots as an educational tool is particularly interesting because of their potential to support collaboration, their capability to trigger physical activity and their inherent attractiveness. However, despite their many benefits, few works have considered the use of robots with children aged under 6 years and those which are targeted at these very young children do not fully exploit the technology, since the designed robots are fixed in one spot and do not support collaborative and cooperative instruction. This paper therefore evaluates the usability of a tangible-mediated robot with eighty-six kindergarten children (2 to 6 years old) which was designed for collaborative kindergarten instruction. The results obtained proved the suitability of the proposed platform for children from the age of 3 years and lays the foundation for developing new learning activities based on this technology for early childhood instruction.