The Old City, situated literally above the sea, is probably the most beautiful and well-known part of the city.
From the station, go down Calle Francisco Gumá until you come to Calle de Jesús. Here turn right and continue walking. At the second street turn left. Keep following Calle Mayor, one of the liveliest streets in the city. The Old City is at the end of the street. Take the opportunity to explore a bit, passing by the church, City Hall and Miracel Palace, until you come to beautiful San Sebastián beach.
On the way back, head towards the church and go down the stairs at the edge of the sea until you come to Plaza del Baluard. Walk a bit on Paseo de la Ribera and then turn around for views of the Old City and its church.