Some brands have already hung their placards up, offering discounts of up to 50%.
The liberalization of the sales law signed in July 2012 allows stores to be ahead of the traditional July 1 start date.
Sfera, Cortefiel, Bimba and Lola, Women’s Secret, Springfield and H & M are some of the stores that have already begun their sales.
El Corte Inglés will officially begin its sales season one day earlier than usual, on June 30.
It is the first time in its history that the department store giant has advanced its summer sales start date.
The Inditex group, containing the likes of Zara and Massimo Dutti, has made the same decision and will start the summer 2017 sales on the same day this Friday.
Those who wish to take advantage of the sales in Zara, Uterqüe, Pull & Bear or Berskha a few hours before and without having to bear the long queues in the first few days, can do so through their online stores at midnight the night before.