Anonymous
After the park closes (around 10:00 PM), you can sleep there. You might hear some noise from the nearby highway. We left the van there for free all day to visit Bilbao by metro (10 minutes away). The toilets are available, but you'll need to bring your own toilet paper. There are nice walks through the park with a beautiful view of Bilbao. During the summer evenings, the barbecue areas are often occupied.