Hydrogels can be used as an alternative coating material for ships against marine biofouling. However, the adhesion of wet and soft hydrogels onto solid metals remains a challenging problem. Here we report the adhesion of a typical hydrogel material, poly(vinyl alcohol) (PVA)-glycerol hydrogel, onto stainless steel substrates and the antifouling potency of the adhered PVA-glycerol hydrogels. Poly(allylamine hydrochloride) (PAH) hydrogel and ethyl α-cyanoacrylate (ECA) are used as the binders, and they are found to be able to firmly bond the PVA-glycerol hydrogels onto the stainless steel substrates. The PAH hydrogel does not affect the mechanical properties of the PVA-glycerol hydrogel during use, but it tends to lose the adhesive ability in a dehydrating environment. In contrast, the ECA adhesive can maintain strong bonding between PVA-glycerol hydrogels and substrates upon several water losing/water absorbing cycles, despite some negative effects on the strength of the PVA-glycerol hydrogel. Biological experiments show that the PVA-glycerol hydrogel has a strong settlement-inhibiting effect on the barnacle Balanus albicostatus, suggesting that combining the PVA-glycerol hydrogel with ECA adhesive may have promising applications in marine antifouling.