Here are some useful addresses and phone numbers in San Sebastian:

Tourist Information Office
Address: Calle Reina Regente, 3
Telephone: +34 943 481166
Opening Hours: 8:00 a.m. to 8:00 p.m., Mondays to Saturdays
10:00 a.m. to 2:00 p.m., Sundays
Note: this is the schedule during summers

Bus Station
Address: Plaza de Pio XII

Train Station
Address: Paseo Francia, s/n

Post Office
Address: Paseo de Francia, nº1
Opening hours: 8:30 a.m. to 8:30 p.m., Mondays to Fridays. Open during the mornings on Saturdays.