In 1383, the King Juan I of Castile, granted the Carta Puebla (Chartae Populationis) in the neighbours of Aizama in order to populate the place, and that’s how Zestoa-Cestona was founded.
In 1486 the terrain of Bedúa became part of Zestoa. In that area taxes were collected, for offloading the minerals melted in the forges of Urola river and the ingots exported to other ports.
Since 15th century Zestoa was one of the eighteenth cities where Juntas Generales de Guipúzcoa (a self-government meeting) was organized. Especially in the Juntas held in Zestoa in 1527 it was issued that no Jewish or Moorish descendant could leave close to Guipúzcoa. That would be the legal basis that sustained the universal nobility of the people of Guipúzcoa.
The year 1667 was when the first bullfights were reported, a tradition that is maintained until our days. In 2012 a referendum was organized in order to be decided whether the tradition should continue or not, and those in favor won.
In 1760, it was noticed that the dogs of Marquis of San Millán were cured from scabies after dipping in some hot water pools. Thanks to that story, the sulphurous waters that would give fame to the place were discovered. In 1792, the waters were declared of public use and in 1804 the Balneario de Cestona, its spa, opened its doors, at the time when other famous spas did so, that happened in 21st century.
These spa centers were set as big facilities where, the aristocracy, the bourgeoisie, artists and politics, apart from enjoying a therapeutic treatment, they could establish important social relations. Zestoa became a popular place quite this way. In 1830, the Infante Francisco de Paula Antonio, brother of Fernando VII and since then the place gained great popularity until is stood out as a main holiday destination in the Basque Country. In 1894 the Gran Hotel was built, as an attachment to the spa resulting from a growing number of visitors, with a triple annual average in ten years. The twenties of the twentieth century were the golden age of Cestona and of its spa, at the same time with the Belle Epoque in San Sebastián. Nowadays, it´s the only spa with such characteristics in the Basque Country.