The development of new advanced materials with self-healing ability targeting underwater applications is reviewed. This challenging task requires a particular approach of water-insensitive dynamic chemistries. Among them, the nature-inspired group of catechol-based functional materials is widely utilized due to the proof of the success of the mussel byssus on underwater self-healing and adhesion. Interestingly, self-healing can be manipulated on demand by incorporating active materials such as redox species or magnetic particles into the matrix of the self-healing polymer. Finally, the underwater applications of these self-healing materials, as a proof of concept of some electrochemical and electronic devices are relatively novel at the moment. However, these materials are expected to make a large impact on technologies in the near future.