Cover the side of the bathtub with wainscoting to give it a rustic look. Use waterproof glue to attach a piece of wainscoting that coordinates with the rest of the bathroom, such as whitewashed, knotty pine or walnut.
Add tile to the side of your bathtub. Use tile that matches the rest of the tile in your bathroom, or use a different type of tile to make the bathtub pop. Install the tile with grout and apply it in standard vertical columns or horizontal rows, or use the tile to create a decorative pattern or mosaic effect.
Give the tub a natural look by covering the side of it with river rocks. Apply grout to the side of the tile and randomly set river rocks in the grout. Use a single color to create a uniform look or opt for different colored rocks for a more eclectic look.
Paint the side of the tub. Use a high-gloss, waterproof, acrylic polymer paint. Paint the side of the tub a solid color that matches the walls or the color of the tiles in the bathroom. For a more artistic look, use different colors of paint to create a pattern or design on the side of the bathtub.