This paper presents an absolute band gap (BG) by overlapping coupled band gaps based on frequency locking mechanism within a wavy structure. We first introduce coupled BG’s trigger conditions, including weak coupling, and then utilize two coupling in a wavy structure to lock three wave modes into two overlapped coupled BGs. A wavy specimen is determined for experimental validation, by selecting the geometric parameters based on their individual effects on the coupled BG. Four testing loads with the capability to excite all guided waves are applied numerically and experimentally to verify the performance of the absolute BG. The response signals validate the existence of a wide attenuation band introduced by the absolute BG. The results exhibit a great potential for utilizing the frequency locking mechanism to construct an absolute BG for applications such as vibration control.