The best thing to do in San Sebastián is tour the bay along Paseo de la Concha and Ondarreta Beach until you come to the sculpture "Peine de los Vientos" (Comb of the Wind). We recommend walking the entire length of the bay, going to see the "Peine de los Vientos" sculpture, riding the funicular to the top of Monte Igueldo and on the way back going up to Miraconcha Palace for the views of the city, and then returning to the centre on Avenida de Miraconcha (1hr. 30min. round trip, not including going up the mountain).
La Concha beach is probably the most famous urban beach in the country. Its odd shape, the big tides, and, above all, the beautiful balustrades and street lamps along its promenade make it one of the most beautiful beaches in the world. In summer its packed with people who come to the beach to sun themselves and cool off in the water, though swimmers can be seen throughout the year, especially senior citizens, regardless of whether it's raining or bitter cold. A daily dip in the La Concha waters, it is said, is the equivalent of immersing oneself in the fountain of youth.
Midway along Paseo de la Concha is the La Perla, today a modern thalassotherapy centre and formerly a spa for San Sebastián 's upper class. In it you'll find two nice cafes with outdoor seating and views of the bay. Café de la Concha offers breakfast for 4-5€, while the area outside La Perla Café is a more like a hamburger bar (hamburgers 5€). Soft drinks cost 2.40€ in both places.
Just above the passage way from La Concha Beach to Ondarreta Beach is Palacio de Miramar (Miramar Palace), an English-style palace built in 1893 at the request of Queen María Cristina (wife of Alfonso XII), who then transferred the summer court of the royal household here. Today it is public property and has some beautiful gardens worth visiting for the breathtaking view of the city below. Do it on the way back, since from the gardens you can pick up Paseo de Miraconcha, which leads back to the city centre along a different route and permits a closer view of the beautiful houses in this neighbourhood.
For years Ondaretta has been the hippest beach in San Sebastián . Frequented by diplomats at the beginning of the previous century, it was the only beach where it was permitted to wear a bikini, which made it the premier pick-up hub in the city. Today it's still a very chic beach, though rocks along the shoreline make it less conducive for swimming than La Concha or Zurriola.
At the end of Ondarreta, following the coast, you'll come to Paseo de Eduardo Chillida, and at the end of it, adjoining the sea, his famous sculpture "Peine de los vientos" (Comb of the Wind).