Surfactants are mainly used as mixtures to obtain the foam properties which are suitable for use and purpose. In this study, it was found that a mixture of glycinate- and glutamate-based surfactants produced a relatively rigid foam compared to that of single component only when the mixture was diluted with tap water and not deionized water. When the surfactant mixtures were diluted with deionized water, the foam hardness was linearly dependent on the weight fraction of the glycinate based surfactant. Meanwhile, the mixtures diluted with tap water produced foam which could withstand vertical loads. We observed the rheological behavior of the air-water interface to understand the ideal and nonideal mixing effect of amino acid-based surfactants. It was confirmed that the synergistic effect on the interfacial modulus and the foam texture was due to the divalent ions of tap water. However, the interaction by the divalent ions did not affect the foam stability. It is worth to noting that the existence of divalent ions is one of the important factors that should be considered to control the foam quality as well as interfacial rheology.