The disclosure concerns a door assembly for a walk-in bathtub that includes a door that fits within a door threshold in the wall of the walk-in tub. The door assembly further comprises a hinge assembly that includes a first axis mount coupled to the door threshold and a second axis mount coupled to the outer side of the door. A double axis hinge is coupled to both axis mounts, to thereby connect the door to the bathtub. The double axis hinge is able to open the door towards the inside of the tub by pivoting about the first axis toward the inside of the bathtub as the door in turn counter rotates about the second axis at the distal end of the hinge, in the direction opposite to that of the hinge.