Both paint and wallpaper can work in a bathroom, provided you choose high-quality products in either category. Washable vinyl wallpapers can stand up to bathroom humidity without peeling, as can semi-gloss or gloss paint finishes. However, if you’re someone who likes to redecorate often, paint may make it easier to change colors or designs more quickly. If you want full humidity protection and cleanability, tile or stone works better.

Textured or patterned vinyl wallpaper designs are the best option for hiding imperfections. Embossed designs or faux finishes like brick, wood, or linen textures are especially effective at camouflaging dents, cracks, or uneven surfaces. Avoid smooth, shiny finishes, as they can highlight flaws rather than conceal them. 

If you can already see the texture of the existing wallpaper through the layer of paint, then the texture could also come through the new layer of wallpaper. If that’s the aesthetic you want, then proceed. But if you want a smoother surface, you should either strip off the existing paint and wallpaper or hang a layer of liner paper before proceeding.

Ideally, you want to ask the wallpaper installers you’re considering for examples of past work, and references you can call. These will prove that the installer can handle your job, make your room look professional, and will also give you some insight into the kind of customer service you can expect. Before you start calling companies, you might want to narrow down your options by finding installers with mostly positive reviews online.