This paper presents the design and optimization process for the new compliant rotation joint. The rotation joint consists of two rings connected together by three branches. Each branch is a combination of circular arcs to create large deformation. Design and optimization process is carried out in 5 steps. The firstly, the mechanical design of the rotation joint is performed. The secondly, the experiment is built using the full factorial experimental design, the joint behavior is investigated using finite element analysis (FEA). Then, the approximate model is built using an Adaptive Neuro-fuzzy Inference System (ANFIS). Next, the parameters of the rotation joint are optimized using the water cycle algorithm (WCA), and finally, optimal results are confirmed through testing.