Abstract This paper presents current technology and research activities related to underwater monitoring. Main focus is directed towards the wireless solutions, built with basis in underwater transponder technology where wireless communication is implemented through acoustic communication. The communication network described is a multi-hop network with autonomous handling of critical tasks as signal routing, and capable of handling both stationary and mobile sensor node within the network. Sensornodes in the network is built by interfacing various subsea sensors to the network communication transponders or AUV's. R&D is also including a cabled infrastructure that can be used together with the wireless solution. Different sensors are selected based on the application targeted, like acoustic sonars or dissolved hydrocarbon sniffers for subsea leak detection. The goal for these R&D activities is to develop and test a versatile and scalable system that can be tailored to different applications, including environmental, military or surveillance in order to effectively provide real-time subsea data to topside.