In early design process, designers employ several media for externalizations of their design ideas which facilitate decision making, discussion and evaluation. Especially models are the most common representation tools and are used generally to understand and make spatial reasoning on the design ideas. Besides the traditional methods, today, the technological developments bring new ways for collaboration and design in 3D; the mobile augmented reality (MAR) technology is one of them. MAR is augmented reality technology which is provided by mobile devices. This study focuses on the early design process of collaborative designers' communication when they are working with the MAR technology. We developed a MAR environment for designers, and conducted an experiment to understand the key elements of the interaction of the designers with the interface. The communication and interaction of the designers are analyzed using the protocol analysis method. The results show that the MAR technology supports the co-design activities encouraging the designers to manipulate the created artefact. The results of the study would be indicative for future studies.