If you are planning, or have already booked, a trip to San Sebastian, you probably should check the best things to do in San Sebastian in advance.
Above all, the extensive range of exclusive activities will definitely make your stay in San Sebastian unique.
In San Sebastian you can have extraordinary experiences that you will look back on for a long time. It is most recommended booking those activities in advance, if you do so you are guaranteed to get a ticket plus you will have more free time on your vacation :)