Take the family for a stroll along the Paseo Nuevo (built 1916) which skirts Monte Urgull from the Aquarium at the harbour to the Calle Salamanca.
It has breathtaing views of the Bay of Biscay and the coast of Gipuzkoa, and small folk enjoy the breaking waves. You may even get a good splash. Once your worn out, make your way toward for pintxos.
Read the full Small Folk Travel San Sebastián Guide.
Image: San Sebastian Tourism