«Donostia» and «San Sebastián» actually refer to the same city, but in different languages. Donostia is the Basque name for the city, while San Sebastián is the Spanish name. The city is located in the Basque Country region of Spain, where both Basque and Spanish languages are spoken.

The use of both names reflects the bilingual and culturally diverse nature of the region. «Donostia» is the name that is commonly used in Basque, which is the indigenous language of the Basque Country. On the other hand, «San Sebastián» is the name used in Spanish, which is the official language of Spain.

It’s worth noting that the Basque Country has a strong cultural identity and a distinct linguistic heritage. Many places in the Basque Country have both a Basque name and a Spanish name, and both languages are actively used in daily life, official communications, and signage.

So, in essence, «Donostia» and «San Sebastián» refer to the same city, with «Donostia» being the Basque name and «San Sebastián» being the Spanish name. The choice of which name to use often depends on the context and the language being spoken.