To enhance properties of a biofouling release coating for a sufficient time by exposing the surface of the biofouling release coating to a restorative compound.

The surface of a biofouling release coating preferably containing a silicone-based polymer, e.g. a polydialkylsiloxane of formula I {R1 is hydroxyl or a group of formula II [R3 and R4 are each a hydrocarbon; (a) is 0 or 1]; R2 is a hydrocarbon or a fluorinated hydrocarbon; m is a number at which the viscosity of the compound of formula I becomes up to about 50,000 cp under an ambient condition of temperature and pressure} is exposed to a restorative compound, e.g. a polyorganosiloxane (e.g. a polyalkylsiloxane, a polymethylphenylsiloxane, a hydrophilic siloxane and a carbinol-functional siloxane), a crude oil product (e.g. a paraffin wax, a petroleum wax, a petrolactam, a grease) and a wax, preferably for 10 hr or more.