A first stage pressure regulator is provided. The regulator includes a valve body having an inlet and an outlet coupled by a pressure chamber. A pressure compensation chamber fluidly communicates with the surrounding water. A valve member is slidably carried by the valve body between an open state in which fluid is permitted to flow between the inlet and outlet and a closed state in which fluid is prevented from flowing between the inlet and outlet. The valve member has an expansion head that is operably acted upon by the surrounding water within the pressure compensation chamber to bias the valve member toward the open state. The regulator includes an annular insulating bushing within the compensation chamber that covers a portion of the valve body defining a portion of the pressure compensation chamber to insulate the valve body from the water within the pressure compensation chamber.