The study presents an ultrafast underwater self-healing piezo-ionic elastomer (MESHPIE) inspired by the self-healing properties and mechanosensitive ion channels of cephalopod suckers. The material is designed with dynamic hydrophobic-hydrolytic domains, incorporating hydrophobic C–F groups and hydrolytic boronate ester bonds. This design enables outstanding self-healing efficiencies in both air (94.5%) and water (89.6%) with remarkable pressure sensitivity (18.1 kPa−1). The integration of MESHPIE into an underwater submarine demonstrates its potential for underwater robotics and human-machine interactions. The material's self-healing capabilities are attributed to the synergistic effect of hydrophobic interactions and boronate ester bond hydrolysis, while its mechanosensitive piezo-ionic dynamics are facilitated by ion-dipole interactions between C–F groups and ionic liquid (IL) cations. The device's performance is validated through pressure-induced tactile sensing and LED modulation, showcasing its potential for practical applications in soft electronics and underwater environments.The study presents an ultrafast underwater self-healing piezo-ionic elastomer (MESHPIE) inspired by the self-healing properties and mechanosensitive ion channels of cephalopod suckers. The material is designed with dynamic hydrophobic-hydrolytic domains, incorporating hydrophobic C–F groups and hydrolytic boronate ester bonds. This design enables outstanding self-healing efficiencies in both air (94.5%) and water (89.6%) with remarkable pressure sensitivity (18.1 kPa−1). The integration of MESHPIE into an underwater submarine demonstrates its potential for underwater robotics and human-machine interactions. The material's self-healing capabilities are attributed to the synergistic effect of hydrophobic interactions and boronate ester bond hydrolysis, while its mechanosensitive piezo-ionic dynamics are facilitated by ion-dipole interactions between C–F groups and ionic liquid (IL) cations. The device's performance is validated through pressure-induced tactile sensing and LED modulation, showcasing its potential for practical applications in soft electronics and underwater environments.