The OCU found a €1,676 yearly difference between the cheapest and most expensive supermarket options in San Sebastián. Irun's average grocery bill is higher still, at €6,880.
The OCU counted 244 products across 80 categories in its 2026 comparison. In San Sebastián, that survey found a €1,676 yearly gap between the cheapest and most expensive supermarket options. The difference is more than double the €743 recorded in the previous OCU study.
Donostia's average annual basket already costs €6,751. Only Barcelona is more expensive among Spain's provincial capitals. San Sebastián and Bilbao follow. The national average is €6,600, so a typical Donostiarra pays more before choosing a store.
The 2026 OCU comparison covered 244 products across 80 categories, giving the price gap a broad basis beyond a small sample of staple goods.
Irun is costlier still on the average basket. The annual bill there reaches €6,880. The gap between the city's cheapest and most expensive options is €1,696.
The OCU collected 101,520 prices across 690 establishments in 38 cities. Its figures put the possible saving in San Sebastián at €1,676, compared with €1,310 across Spain. The research was published on 25 September 2026. El País independently confirmed the survey's scale and its national conclusions.
That is a big gap.
Across Spain, the average annual supermarket basket reached €6,602 in 2026, up 5.18% over the year. Donostia’s €6,751 and Irun’s €6,880 therefore place both local markets above the national level before the potential savings from changing stores are calculated.
Madrid has the widest city-level spread at €4,381. Torrent, Villarreal and Santa Pola are the cheapest locations in the study. Getxo, Pozuelo de Alarcón, Majadahonda and Cerdanyola del Vallès are among the most expensive. ABC's coverage of the Madrid figure showed how much prices can differ between shops in one city.
Price growth has slowed compared with the previous two years. The OCU basket rose by an average of 1.8%. Fresh products increased 4.7%, fish 8.6%, meat 3.7% and fruit and vegetables 3.5%. Packaged goods rose 1.4%.
Brand-name products became 2% more expensive. Private-label goods rose 0.8%. In total, 61.8% of the basket items increased in price, while 38.2% became cheaper. Tomatoes led the rises at 33.2%. Lemons followed at 25.2%, cauliflower at 22.8%, aubergines at 20.4% and portion-sized John Dory at 19.4%.
Some prices fell sharply. Potato purée dropped 14.8%. Artichokes fell 15.1%, Canary Islands bananas 22.6% and paper napkins 30.4%.
The longer view is harsher. Since 2021, the OCU basket has risen by 39.5% on average. Fresh products are up 44% and meat 46.8%. Economical blended ground coffee has increased 142%, medium eggs 135%, large eggs 123% and a milk chocolate bar 101%. Only laundry detergent, natural Danone yoghurt and rice drink cost less than in 2021.
Price competition between chains has also grown. Eight of the 28 major retailers analysed cut prices. Carrefour Market led with a 2.7% reduction, followed by Lidl at 1.9%, Mercadona at 1.8% and Aldi at 1.4%. BM Urban rose 5.1% and Ahorramás 4.4%. The supermarket landscape rewards comparison, much as earlier household data showed how quickly essential costs can strain family budgets.
Dani remains the cheapest chain overall. Family Cash and Tifer follow, with Alcampo and Supeco also near the top. Alcampo hypermarkets are the cheapest option in many locations. Lidl now leads in 60 cities, compared with 18 a year earlier. Mercadona has doubled the number of places where it is the best-priced choice. Supeco has risen from 18 to 28.
For shoppers in Donostia and Irun, the annual bill depends heavily on where they build their basket. Prices are rising more slowly than before, but the €1,676 and €1,696 gaps still matter. The average basket in both cities is already above the national level. Comparing supermarkets remains one of the few immediate ways to cut a five-figure household expense over several years.
