<p>Remotely operated vehicles, or ROVs, are essential for a variety of underwater applications, ranging from commercial to scientific. Due to their nonlinear dynamics, providing a control method to achieve precise trajectory tracking is a fundamental issue. In this research, a fuzzy two-loop sliding mode controller has been designed for precise trajectory tracking. This designed controller can overcome the dynamic uncertainties of the system properly. The chattering phenomenon, which is a common phenomenon in the sliding mode controller, has been fixed. The cascade system designed for this controller consists of two parts: the external loop (position loop) and the internal loop (velocity loop), and a fuzzy controller is used instead of the outer loop switching function. The implementation of this control method has achieved a remarkable 98% reduction in path tracking error compared to other controllers, including sliding mode, fuzzy sliding mode, and double-loop sliding mode controllers. Lyapunov's stability law is also employed to demonstrate the stability of the cascade system. We believe that using this proposed controller can lead to the reduction of ROV path tracking error and also reduce the chattering phenomenon in the sliding mode controller.</p>