Highly hydrophilic hydrogels are able to potentially act as fouling-resistant coatings to prevent the settlement of marine organisms, due to the inherent surface properties. It is highly desired to improve mechanical and antifouling (AF) performance of hydrogels for durable and effective usage. Herein, a kind of composite hydrogels with enhanced mechanical properties and synergetic AF activity is prepared in a simple and low-cost way. The cooperation of biocidal copper release and non-fouling interfaces is realized, resulting in improved AF performance. Spherical cuprous oxide-tannic acid submicroparticles can be incorporated into poly(vinyl alcohol) (PVA) hydrogels by a freeze-thaw process. The hydrogels exhibit underwater superoleophobicity, improved strengths and moduli, and self-healing ability. Incorporation with the fouling-resistant effect, low-level, sustainable copper release rates endow the hydrogels with improved AF activities against the green alga Chlorella Vulgaris. The low copper release rates also mean the minimized environmental influence. It holds great promise for applying such robust, multifunctional composite hydrogels in long-term AF applications on both dynamic and static conditions. (C) 2018 Elsevier Inc. All rights reserved.