Bus 7 (€4, 30 minutes) runs between the airport and San Sebastián at flight arrival times.
Plan on using your own two feet to get around the town; San Sebastián is very walkable, and is so small that buses merely pass through, not really connecting points of interest within the town centre.
The taxi stand is on Avenida Descubridores. The only reason you might need a car is to move between the town centre and the Parador Nacional Conde de la Gomera, which is a short (though steep) walk or drive away. If you’re going further afield, a car is very useful.
There are several car-rental agencies around, and they will arrange to have a car waiting for you at the port or airport when you arrive if you book ahead, which is recommended.
Cicar There is also an office at the airport.
Rent-a-Car La Rueda A reasonably priced local car-rental agency.