We stayed 4 days in San Sebastian with our 2 kids (11 and 12 yo).
The Mikel apartment is perfectly located for people who want to stay in the city center : between Gros and Old Town, with La Bretxa market at the end of the street, Boulevard parking at 5 mins walk..
and in a calm and clean street which is very important for the nights, especially with kids !
The apartment is also very clean and have absolutely everything you need to live a perfect moment in San Sebastian (even 2 bathrooms, one for each bedroom !)
Mikel is a great host and he gave us lot of good advices : thank you Mikel and we will definitely not hesitate to come back !!