The demand for smart, durable, and energy-independent lubrication materials in wet or dynamic environments remains unmet due to limitations in conventional stimuli-responsive coatings. Inspired by mucus-secreting fish, which achieve rapid, passive lubrication through internal secretion and structural adaptation, this work presents a water-triggered self-lubricating epoxy coating (EP-HAG) incorporating hydrophobically associated superabsorbent hydrogel (HAG) particles. The design addresses key challenges of conventional systems by enabling spontaneous surface lubrication without external stimuli and by introducing intrinsic self-healing ability. Under wet conditions, the partially exposed HAG particles swell to form a water-rich lubricating layer, while the embedded portion ensures mechanical anchoring. Compared to pure epoxy, the optimized EP-HAG9 coating reduces the coefficient of friction and wear rate by ∼66.0% and ∼86.6%, respectively, under typical conditions (150 rpm, 5 N). Additionally, the physically crosslinked HAG network enables structural self-repair after shear damage, maintaining long-term low-friction performance. Functional demonstrations, including underwater escape and passive leak-triggered alarms, confirm the coating's potential for intelligent release and sensing. This study offers a biomimetic, energy-free lubrication strategy with broad implications for smart coatings and protective materials in humid or aquatic applications.