The fortress
Restored and used as a cultural space, the castle and its gardens are an easy first walk on arrival day — short enough for children, interesting enough to anchor an afternoon. Check current opening hours locally before you go.
The streets around it
The surrounding blocks are the everyday La Isleta: small shops, bars where the neighbourhood drinks coffee, and views of the port. Walking from the castle towards Las Canteras takes you across the peninsula in a few minutes.
Combine it with the beach
A common half-day: castle in the morning, market or supermarket on the way back, then the ten-minute walk to Las Canteras for the afternoon and dinner on the rooftop.