The Chapel of San Nicolás first appears in 1634 as a place of meetings and worship for Algorta’s seafarers, dedicated to their patron saint. It thus satisfied the need for a place to carry out these two basic functions inside the port district itself. Built on a rock at the bottom of San Nicolás street, the chapel had a single rectangular nave with a three-sided apse. It was a small building done in masonry with ashlars at the corners and openings. It was crowned with a simple belfry and a front portico.
When the seat of the Seafarers’ Brotherhood moved to Etxetxu House and the new Church of San Nicolás was built in Algorta in the 19th century, the building was reformed and adapted for new purposes. By 1870 it had become a Sailing School, thanks to the agreement reached between the Town Hall and the Brotherhood. Subsequently, its morphology was changed as required to fulfil its different functions – such as school teacher’s house, prison, warehouse, social centre, barracks and police station. The transformations it underwent over its life have altered it so that it barely resembles its original design, through to today when it is now a residential building - number 23, San Nicolás street.