An underwater electrical connection assembly is provided, where the assembly includes (1) a contact pin including an axially extending conductive core and an axially extending annular insolation portion around the conductive core, (2) a front end portion of the conductive core having an electrical contact surface, (3) a rear end portion of the conductive core having an electrical contact surface, and (4) an intermediate portion of the conductive core extending axially at an intermediate location between the front and rear end portions. In the assembly, the rear end portion of the conductive core of the pin includes a diameter larger than the diameter of the intermediate portion thereof, and the annular insulation portion includes an inner insulating layer around the intermediate portion of the conductive core and an insulating sleeve around the inner insulating layer.