A fluid pressurization unit compresses a fluid in response to natural wave action on a body of water such as an ocean. The unit comprises a floating component and a piston assembly. The floating component has sufficient buoyancy to float on water waves and has a compression chamber with an inlet valve biased to receive a fluid at an intake pressure. The piston assembly is slidable within the compression chamber and has a piston shaft and a hollow piston head attached to the piston shaft, which defines a piston reservoir therein with an inlet valve in communication with the compression chamber and biased to receive the fluid at an output pressure, and an outlet for discharging fluid pressurized to at least the output pressure from the pressurization unit. The piston assembly is fixable in place relative to the floating component such that relative movement between the floating component and piston assembly compresses fluid from the intake pressure to at least the output pressure.