A new juice market, consisting of mixtures of fruits, is expanding in the beverage segment, in order to increase even more the nutritional and sensory characteristics. In addition, in the preparation of juices, the option exists to replace water with coconut water. The aim of this study was to develop and optimize mixed juices based on coconut water and berries (strawberry, blackberry, and red raspberry), through the mixture design, desirability function, and response surface methodology. Mixed juices were evaluated by rheological, physical, physicochemical, sensory, and nutritional characteristics. The treatments produced with strawberry (50% or 100%) were preferred among the tasters, and the juices elaborated using blackberry contributed to higher viscosity, antioxidant activity, phenolic compounds, and total anthocyanins. According to optimization, the mixed juices should contain 50-60% strawberry, 40% blackberry, and 0-10% raspberry. Thus, the mixed juices produced from these fruits have better characteristics than the juice of only one fruit type.