Centrally located if you want to stay in the older part of Bilbao. We stayed just one night but the apartment is well equipped with everything you would need. We were a family of 5 and it was still comfortable. A stylish apartment and the photos are quite accurate. To add, there are 2 bakeries beside the apartment (1 vegan).
Serafin responds to messages very quick which I appreciated especially when we realized we left something in the apartment and had to head back. Alvaro who met us for the keys and the parking was also very nice. Would recommend the place and stay there again.