The apartment has a proper kitchen, and most guests use it. Here is where to fill it.
In the village, on foot
There is a small supermarket at Playa de San Marcos, a few minutes downhill, with a pharmacy directly next door. It is better stocked than its size suggests — bread, milk, coffee, wine, basic vegetables, the things you discover you need at eight in the evening.
Treat it as the shop for what you forgot rather than the shop for the week. It is the only food retail within walking distance, and having a pharmacy beside it matters more than it sounds: Spanish pharmacists deal with plenty that would need a doctor’s appointment elsewhere.
The weekly shop, by car
About eight minutes away you have the full range. Lidl sits on the road heading towards Puerto de la Cruz, and Mercadona and HiperDino are up in Icod de los Vinos.
Mercadona is the Spanish standard and the best all-rounder. HiperDino is the Canarian chain and usually the strongest on local produce — island cheeses, local wine, the good tomatoes. Lidl is Lidl, and it is where you charge an electric car.
Better than any of them: the markets
If your stay covers a weekend, go to a mercado del agricultor instead. La Guancha runs at weekends and Los Silos on Sunday mornings, both wrapping up around 2 pm.
This is where the produce is actually good — fruit and vegetables grown on these slopes, island goat cheese, bread from a local baker, honey, and wine from growers who may well be pouring the same bottles in a guachinche later in the season. Bring cash and go early.
One practical note
Sunday is quiet. The big supermarkets keep limited hours or close, and the village shop is your fallback. If you are arriving on a Sunday, plan the first shop around that — the same rhythm that governs when restaurants open applies to the shops.