The development of ionotronic hydrogels that can transmit electrical signals and withstand mechanical deformation holds great promise for applications in soft electronics and human–machine interfaces. However, their operational durability is often compromised by mechanical damage, such as cracks and punctures. Herein, we report a sea cucumber-inspired ionotronic hydrogel that features room-temperature self-healing capability and interfacial capacitive sensing. Reversible ionic electrostatic interactions and dynamic hydrogen-bonding networks impart effective self-healing, whereas pressure-induced interfacial contact evolution coupled with electrical-double-layer formation and ionic modulation at the hydrogel-electrode interface enables sensitive capacitive signal transduction. The obtained hydrogel exhibits stretchability exceeding 1000%, high ionic conductivity (> 0.49 S·m⁻¹), and strong adhesion and effective self-healing capability. In addition, we demonstrate that the hydrogel-based ionotronic sensor achieves a high sensitivity (~ 20.6 kPa⁻¹), a wide detection range of up to ~ 1 MPa, rapid response/recovery time of ~ 30/40 ms, and excellent stability under various mechanical loading conditions. As a proof of concept, a hydrogel-based tactile sensing glove achieves real-time, robust tactile sensing, shape recognition, and directional-intent decoding, allowing reliable human–machine interaction control. This work provides a simple strategy for developing adhesive, self-healing ionotronic platforms for wearable sensing and human–machine interaction.