Diana's apartment is amazing. I can't think of a better place to stay in San Sebastián. Check in and communication were amazing. She was so nice and accommodated our late arrival as we took the train from Barcelona.
The apartment was very clean and well equipped and had everything you needed for a stay. Having a washing machine was key as we were in Spain for 2 weeks.
It is walking distance (literally minutes) away from the main attractions and the train station. It couldn't be any better located. The San Martin market is a 2 minute walk, which was great for getting food/groceries.
Bed was comfy, shower was great (and the products were high class!), and internet was super fast. The balcony is wonderful for having a coffee and pastry in the morning. Would stay here 100 times again!