Spanish flats are heavily tiled, and the bathroom is usually tiled on every wall. That is good for damp and awkward for anyone holding a drill, because a hole in glazed ceramic cannot be filled and painted over the way a hole in plasterboard can.
This is a guide to fitting out a rented bathroom without making one. Everything below is reversible, and most of it moves with you to the next flat.
What Spanish law actually says about drilling
Article 23 of the Ley de Arrendamientos Urbanos is the relevant rule. A tenant may not carry out works that modify the configuration of the dwelling without the landlord's consent, expressed in writing. If you do the work anyway, the law lets the landlord require you at the end of the contract to restore the property to its previous state, or to keep the modification, with no compensation to you either way.
Whether a wall fixing counts as modifying the configuration is a judgement call that depends on your contract and the damage done. The practical point stands: get written permission before you drill, or use fittings that need no fixing at all.
Adhesive fittings

The Towel Rail Torino is a stainless steel bar on an adhesive mount, with no wall fixings. It holds hand and bath towels without sagging. At 27.16 euros it is the cheapest way to get a towel off the floor in a bathroom you do not own.
If you already own holders from the BERNO S or M range, the adhesive mounting kit converts them to drill-free for 8.57 euros. It uses double-sided mounting tape rated for tiled and smooth surfaces.
Two honest limits. Adhesive needs a smooth, sound surface, so unglazed or heavily textured tile and painted walls are outside what these products are rated for. And neither product page states a maximum load, so treat a towel rail as a towel rail. If you need a fitting that takes body weight, that is a mechanical fixing, a drill and a conversation with your landlord.
The freestanding route

If the wall is painted or the tile is textured, do not touch it at all.
The freestanding towel rack in black iron is 48 by 24 by 79 cm with three levels, and doubles as a drying rack. It costs 72.06 euros and needs nothing but floor space. Over a washing machine, the Sonoma oak storage rack is 67 by 25 by 163 cm and uses the vertical space most rented bathrooms waste.
The Lund toilet brush holder is stainless steel with a removable inner container, and is built to work either wall mounted or standing on the floor. In a rental, stand it on the floor. Smaller still, a matt ceramic toothbrush holder sits on the basin and needs no decision at all.
A drill-free bathroom, assembled
A workable set for a rented flat is one adhesive rail for the bath towel, one freestanding rack for everything else, a floor-standing brush holder, and a basin-top holder for toothbrushes. That covers daily use without a single fixing, and all of it comes with you when the contract ends.
The full range sits in Bathroom Accessories and the wider Bathroom collection. If you are furnishing from empty, our towels and robes are the other half of the job.
Shop drill-free bathroom fittings
More on how we choose what we stock: Born in Barcelona, Made for Your Home.

