Excellent stay at this apartment. Very central and is located in a neighborhood that is less touristic.
It also has a direct view on the ocean.
During high season it is a bit pricey, but we did enjoy the comfort of the bed and overall quality of the apartment.
One negative point is that we needed to get the keys from the agency which is about 2km from the apartment. Normally not a big deal, but annoying if you have a lot of stuff to carry and no car.
We will definitely book there again if we come back to San Sebastián